Question

Solve the linear system of equations using the linear combination method.

{8a−4b=205a−8b=62

Answer 1

Answer: a=-2. b=-9

Step-by-step explanation: they are right I took the test and got %

Answer 2

Step 1:

Line up respective variables in column.

`8a-4b=20`.................(1)

`5a-8b=62`.................................(2)

Step 2:

We need to multiply first equation with -2 so that the coefficient of b becomes equal and opposite of -8.

`8a-4b=20` *2

`-16a + 8b=-40` ...................(3)

Step 3:

Add equation (2) and (3)

`5a-8b=62`

`-16a+8b=-40`

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,

`8a-4b=20`

`8(-2)-4b=20`

`-16-4b=20`

b=-9

Answer : a=-2 and b =-9