use the elimination method to find 3a+7b=47 and -3a +b =17

Question

trying to solve the problem

Answer 1

Elimination method

3a+7b = 47----------> (1)

-3a+b = 17 ---------> (2)

To eliminate the a value, add the equations (1) and (2).

3a+7b = 47

-3a+b = 17

_________

8b = 64

Divide to each side by 8.

8b/8 = 64/8

⇒ b = 8

Substitute the b value in (1).

3a+7*8 = 47

3a+56 =47

Subtract 56 from each side.

3a+56-56 = 47-56

3a = -9

Divide to each side by 3.

3a/3 =-9/3

⇒ a = -3

Solution a = -3, b = 8.