Respuesta :

Answer:-3

Step-by-step explanation:

know

a+b=1

a-b=2

by combine the equatio you will get 2a+b-b=3

the b cancal each other out left 2a=3 and 3/2 = 1.5 for a

so if 1.5=a then apply 1.5 into a+b=1 and a-b=2 you will receive -.5 for b and 1.5/-.5 will equal to -3