Question

If 8a−4b=20 and 4a−8b=4, then what is the value of a−b?

Answer 1

1/2

-2(4a-8b=4)

=

-8a+16b=8

+8a-4b=2

——————

0+12b=-6

/12. /12

B= -1/2

Plug it in

4a-8(-1/2)= 4

4a+4=4

-4. -4

4a=0

/4. /4

A=o

Finish by plugging a and b in for the last part

0-(-1/2)

= 1/2