Question

The sum of x and y is 280. If x + 8 is y, when will the value of x be the same for both equations?

Answer 1

the answer is x=136

Explanation:

x + y = 280

x + 8 = y (substitute this expression for y)

x + (x + 8) = 280

2x + 8 = 280

2x = 272 -> x = 136

to find y:

x + 8 = y

136 + 8 = y

144 = y

CHECK:

136 + 144 = 280

yes

Answer 2

x = 136, y = 144

Explanation:

x+y = 280

y = x +8

use substitution

x + x+8 = 280

2x = 272

x = 136

y= 136+8 = 144