Question

$15x-30=99x+10$

Which of the following is the solution to the equation shown above ?

• A. $x=\frac{10}{21}$
• B. $x=-\frac{10}{21}$
• C. $x=\frac{21}{10}$
• D. $x=-\frac{21}{10}$

Answer 1

The correct option is B $x=-\frac{10}{21}$

Solution to an equation is a value for the variables (in this case $x$) that makes the equation true.
Let’s find an equivalent equation by first subtracting $99x$ from both sides, then adding 30
$15x-30-99x=99x-99x+10$
$-84x-30=10+30$
$-84x=-40$
$x=\frac{-40}{84}$
$=\frac{-10}{21}$
The solution is $x=\frac{-10}{21}$

Hence, the correct answer is option B