Question

In the following equations, a and b are equal. Which number could be substituted for both a and b to make both equations correct?

15x0=-36+a
24x8x0=36-b
a.-36
b.51
c.36
d.-51

Answer 1

The Answer is c. 36

Proof.

Solve the following system:
{0 = a - 36 | (equation 1)
{0 = 36 - b | (equation 2)

Express the system in standard form:
{-a+0 b = -36 | (equation 1)
{0 a+b = 36 | (equation 2)

Multiply equation 1 by -1:
{a+0 b = 36 | (equation 1)
{0 a+b = 36 | (equation 2)

Collect results:

Answer: {a = 36 {b = 36