Step 1:
Line up respective variables in column.
[tex] 8a-4b=20 [/tex].................(1)
[tex] 5a-8b=62 [/tex].................................(2)
Step 2:
We need to multiply first equation with -2 so that the coefficient of b becomes equal and opposite of -8.
[tex] 8a-4b=20 [/tex] *2
[tex] -16a + 8b=-40 [/tex] ...................(3)
Step 3:
Add equation (2) and (3)
[tex] 5a-8b=62 [/tex]
[tex] -16a+8b=-40 [/tex]
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,
[tex] 8a-4b=20 [/tex]
[tex] 8(-2)-4b=20 [/tex]
[tex] -16-4b=20 [/tex]
b=-9
Answer : a=-2 and b =-9
