Answer:
43 and -12
Step-by-step explanation:
let x be 1st number and y be 2nd number.
x + y = 31
x - y = 7 (eqn 1)
x = 31 - y (eqn 2)
substitute eqn 2 into eqn 1,
31 - y - y = 7
31 - 2y = 7
24 = -2y
y = -12
substitute y =-12 into eqn 2,
x = 31 - (-12)
x = 31 + 12
x = 43
1st number is 43, 2nd number is -12
