Algebra 1 : Linear / Rational / Variable Equations

Study concepts, example questions & explanations for Algebra 1

varsity tutors app store varsity tutors android store

Example Questions

Example Question #3 : Solving Equations And Inequallities

Solve for \(\displaystyle x\):

\(\displaystyle 8x-5-4x=-x+10\)

Possible Answers:

\(\displaystyle 2\)

\(\displaystyle 4\)

\(\displaystyle 6\)

\(\displaystyle 5\)

\(\displaystyle 3\)

Correct answer:

\(\displaystyle 3\)

Explanation:

\(\displaystyle 8x-5-4x=-x+10\) can be simplified to become

\(\displaystyle 4x-5=-x+10\)

Then, you can further simplify by adding 5 and \(\displaystyle x\) to both sides to get \(\displaystyle 5x=15\).

Then, you can divide both sides by 5 to get \(\displaystyle x=3\).

Example Question #1 : How To Find The Solution To An Equation

What number is six less than eight more than one half of four times the square of the greatest negative integer?

Possible Answers:

\(\displaystyle 4\)

\(\displaystyle -6\)

\(\displaystyle 0\)

\(\displaystyle 11\)

\(\displaystyle \frac{1}{3}\)

Correct answer:

\(\displaystyle 4\)

Explanation:

Turn the word problem into math.  Start at the end--what is the greatest negative integer?  -1!

\(\displaystyle (-1)^2\cdot4\cdot\frac{1}{2}+8-6=1\cdot4\cdot\frac{1}{2}+8-6=2+8-6=4\)

Example Question #1 : Linear / Rational / Variable Equations

\(\displaystyle 18\div\frac{1}{6}\cdot\frac{9}{72}\cdot\frac{4}{27}\cdot(-8+7)^9=\)

Possible Answers:

\(\displaystyle -6\)

\(\displaystyle 9\)

\(\displaystyle 6\)

\(\displaystyle -12\)

\(\displaystyle -2\)

Correct answer:

\(\displaystyle -2\)

Explanation:

\(\displaystyle 18\div\frac{1}{6}\cdot\frac{9}{72}\cdot\frac{4}{27}\cdot(-8+7)^9=18\cdot6\cdot\frac{1}{8}\cdot\frac{4}{27}\cdot-1\)

 

Remember to cancel as you go--the 18 will cancel with the 27, the 4 will cancel with the 8, and so on:

\(\displaystyle 18\cdot6\cdot\frac{1}{8}\cdot\frac{4}{27}\cdot-1= 2\cdot6\cdot\frac{1}{2}\cdot\frac{1}{3}\cdot-1\)

 

Continue to reduce:

 

\(\displaystyle 2\cdot6\cdot\frac{1}{2}\cdot\frac{1}{3}\cdot-1= 2\cdot1\cdot-1=-2\)

Example Question #1 : Solving Equations And Inequallities

Solve for \(\displaystyle x\):

\(\displaystyle 6x-1=12x+8-3x\)

Possible Answers:

\(\displaystyle -6\)

\(\displaystyle -3\)

\(\displaystyle 3\)

\(\displaystyle 1\)

\(\displaystyle 6\)

Correct answer:

\(\displaystyle -3\)

Explanation:

To solve for \(\displaystyle x\), you must first combine the \(\displaystyle x\)'s on the right side of the equation. This will give you \(\displaystyle \ 6x-1=9x+8\).

Then, subtract \(\displaystyle 8\) and \(\displaystyle 6x\) from both sides of the equation to get \(\displaystyle -9=3x\).

Finally, divide both sides by \(\displaystyle 3\) to get the solution \(\displaystyle x=-3\).

Example Question #2 : How To Find The Solution To An Equation

Solve for \(\displaystyle x\):

\(\displaystyle 3x+5=2(3x-2)\)

Possible Answers:

\(\displaystyle -3\)

\(\displaystyle 2\)

\(\displaystyle -2\)

\(\displaystyle 3\)

\(\displaystyle 1\)

Correct answer:

\(\displaystyle 3\)

Explanation:

First, use the distributive property to simplify the right side of the equation: \(\displaystyle 3x+5=6x-4\). Then, subtract \(\displaystyle 3x\) and add 4 to both sides to separate the \(\displaystyle x\)'s and the integers to get \(\displaystyle 9=3x\). Divide both sides by 3 to get \(\displaystyle x=3\).

Example Question #3 : How To Find The Solution To An Equation

Solve for \(\displaystyle x\):

\(\displaystyle a(x+b)= c\)

Possible Answers:

\(\displaystyle \frac{a}{c}-b\)

\(\displaystyle \frac{c-b}{a}\)

\(\displaystyle \frac{a}{c-b}\)

\(\displaystyle \frac{c}{a}-b\)

\(\displaystyle \frac{a-b}{c}\)

Correct answer:

\(\displaystyle \frac{c}{a}-b\)

Explanation:

To solve for \(\displaystyle x\), first divide both sides by \(\displaystyle a\): \(\displaystyle x+b=\frac{c}{a}\). Then, subtract both sides by \(\displaystyle b\) to get \(\displaystyle x=\frac{c}{a}-b\).

Example Question #2 : Systems Of Equations

\(\displaystyle (4^2)^x=64\)

Possible Answers:

\(\displaystyle -\frac{3}{4}\)

\(\displaystyle -2\)

\(\displaystyle 4\)

\(\displaystyle \frac{3}{2}\)

\(\displaystyle 2\)

Correct answer:

\(\displaystyle \frac{3}{2}\)

Explanation:

\(\displaystyle (4^2)^x= 4^{2x}=64\)

\(\displaystyle 64= 4\cdot 4\cdot 4=4^3\)

\(\displaystyle 4^{2x}=4^3\)

\(\displaystyle 2x = 3\)

\(\displaystyle x = \frac{3}2{}\)

Example Question #131 : Equations / Inequalities

\(\displaystyle \frac{4^2+6\cdot 9}{4+3(2)}+\frac{7}{14}\cdot\frac{50}{25}-1=\)

Possible Answers:

\(\displaystyle 8\)

\(\displaystyle 7\)

\(\displaystyle 19.8\)

\(\displaystyle 12\)

\(\displaystyle 9\)

Correct answer:

\(\displaystyle 7\)

Explanation:

1.  First simplify the first expression:

 

\(\displaystyle \frac{4^2 +6\cdot 9}{4+3(2)}=\frac{4\cdot 4+54}{4+6}=\frac{16+54}{10}=\frac{70}{10}=7\)

 

2.  Then, simplify the next two expressions:

\(\displaystyle \frac{7}{14}\cdot\frac{50}{25}=\frac{1}{2}\cdot\frac{2}{1}=1\)

 

3.  Finally, add and subtract:

\(\displaystyle 7+1-1=7\)

Example Question #4 : How To Find The Solution To An Equation

Solve for x.

\(\displaystyle \frac{x^2-x^3-(-x-4)}{\frac{1}{x}+\frac{x}{1}}, x=-2\)

Possible Answers:

\(\displaystyle 12\)

\(\displaystyle \frac{-4}{3}\)

\(\displaystyle \frac{-7}{9}\)

\(\displaystyle \frac{28}{3}\)

\(\displaystyle \frac{-28}{5}\)

Correct answer:

\(\displaystyle \frac{-28}{5}\)

Explanation:

1.  First solve for the numerator by plugging in -2 for x:

\(\displaystyle (-2)^2-(-2)^3-(-(-2)-4)=4+8+2= 14\)

2.  Then, solve the denominator by combining the fractions:

\(\displaystyle \frac{1}{x}+\frac{x}{1}= \frac{-1}{2}+\frac{-2}{1}=\frac{-1}{2}+\frac{-4}{2}=\frac{-5}{2}\)

3.  Finally, "rationalize" the complex fraction by multiplying top and bottom by -2/5:

\(\displaystyle \frac{14}{\frac{-5}{2}}\cdot\frac{\frac{-2}{5}}{\frac{-2}{5}}=\frac{\frac{-28}{5}}{1}=\frac{-28}{5}\)

Example Question #5 : How To Find The Solution To An Equation

\(\displaystyle \frac{x*7+5*4+1}{y*2+4}=3\)

If x/y is equivalent to 12/20, what is the value of x?

Possible Answers:

\(\displaystyle 21\)

\(\displaystyle 3\)

\(\displaystyle 12\)

\(\displaystyle 7\)

\(\displaystyle 9\)

Correct answer:

\(\displaystyle 3\)

Explanation:

\(\displaystyle \frac{x*7 +5*4+1}{y*2+4}= \frac{7x +21}{2y +4}=3\)

 

Multiply both sides by the denominator (2y +4) to cancel it:

\(\displaystyle \frac{7x +21}{2y +4}*(2y +4)=3*(2y+4)\)

\(\displaystyle 7x + 21=6y +12\)

Now, use substitution to solve for x:

\(\displaystyle \frac{x}{y}=\frac{12}{20}-->20x=12y-->10x=6y\)

Substitute 10x for 6y in the first equation:

\(\displaystyle 7x+21=(10x)+12\)

\(\displaystyle 9=3x\)

\(\displaystyle 3=x\)

Learning Tools by Varsity Tutors