Question

What is the most efficient first step to isolate the variable term on one side of this equation? -9x = -4x + 5 A. Subtract 5 from both sides. B. Add 5 to both sides. C. Subtract 9x from both sides. D. Add 4x to both sides.

Answer 1

For this case we have the following equation:

$-9x = -4x + 5$

We want to clear x:

For this we must follow a series of steps, the first consists of adding 4x to both sides of the equation to obtain:

$-9x + 4x = -4x + 4x + 5\\-5x = 5$

In this way, the variable term remains on one side of the equation.

Thus, the first step will be:

Add 4x to both sides

Answer:

Option D

Answer 2

Answer

D. Add 4x to both sides.

Explanation

-9x = -4x + 5

On the right hand side we have -4x. We have to add 4x on both sides to have;

-9x + 4x= -4x + 5 + 4x          

(-4x + 4x = 0)

(-9x + 4x = -5x)

∴ -5x = 5