Question

Slove by using elimination
3x+7y=27
-3x+y=21

Answer 1

x = -5

y = 6

Explanation:

3x + 7y = 27 --------------(I)

-3x + y = 21 -----------(II)

Add equation (I) & (II) and so x will be eliminated and we can find the value of y.

(I) 3x + 7y = 27

(II) -3x + y = 21 {add}

8y = 48

y = 48/8

y = 6

Plugin y = 6 in equation (I)

3x +7*6 = 27

3x + 42 = 27

3x = 27 - 42

3x = -15

x = -15/3

x = -5