Question

Hi! Please explain how you got your answer thanks! :)) ​

Answer 1

a + b = 780

Explanation:

If we subtract the two equations we can ”eliminate“ a and b and find the value of z.

a-a = 0

b-b = 0

-10z = -700

z = 70

now we have to subistitute this value in the two equations

a + b -4(70) = 500

a + b + 6(70) = 1200

a+b - 280 = 500

a + b + 420 = 1200

If we simplify we have

a + b = 780

a + b = 780