Step 1:
Line up respective variables in column.
.................(1)
.................................(2)
Step 2:
We need to multiply first equation with -2 so that the coefficient of b becomes equal and opposite of -8.
*2
...................(3)
Step 3:
Add equation (2) and (3)
The b terms will cancel out and we are left with only a terms.
-11a = 22
dividing both sides by -11
a=-2
Step 4:
plug this value of a in equation (1) to find value of b,
b=-9
Answer : a=-2 and b =-9