Question

What must you subtract from the expression –5x – 8 in order to make it equivalent to –9x – 1 for all values of x?

Answer 1

the number is 4x - 7

Explanation:

Let P be subtracted from -5x - 8 to make it equivalent to -9x - 1.

-5x - 8 - P = -9x - 1

make "-P" the subject of the formula

-P = -9x - 1 + 5x + 8

Collect like terms;

-P = -9x + 5x - 1 + 8

-P = -4x + 7

divide through by "-1"

P = 4x - 7

Therefore, the number that must be subtracted from -5x - 8 to make it equivalent to -9x - 1 is 4x - 7