Question

How to solve 3x+4y=36
y=-1/2x+8

Answer 1

x = 4

y = 6

Explanation:

3x + 4y = 36 ⇒ ( 1 )

y = - 1/2x + 8 ⇒ ( 2 )

( 2 ) × 2

2y = -x + 16 ⇒ ( 3 )

2y + x = 16

x = 16 - 2y ⇒ ( 4 )

Let us replace x with ( 16 - 2y ) and the value of y.

For that, let us use the equation (1).

3x + 4y = 36

3 ( 16 - 2y ) + 4y = 36

48 - 6y + 4y = 36

48 - 2y = 36

48 - 36 = 2y

12 = 2y

Divide both sides by 2.

6 = y

Now let us replace y with 6 and find the value of x.

For that let us use equation 4.

x = 16 - 2y

x = 16 - 2 × 6

x = 16 - 12

x = 4