Find x, when y=2x PLEASE HELP, plz give working out and explain

### 6 Answers

Since y=2x you can replace y with 2x in the first equation. (substitution)

4(2x) + 2x = 150

Then multiply the 4 and 2 to get 8x and add the like terms.

8x + 2x = 150

10x = 150

Then divide by 10 on both sides, the left side is left with just x and your answer on the right.

10x/10 = 150/10

x = 15

[1]4y + 2x = 150

[2] y = 2x

substitute y (from [2]) into [1]

4(2x) + 2x = 150

8x + 2x = 150

10x = 150

x = 15

y = 2(15) – (from [2])

y = 30

4y + 2x = 150 ………. (1)

Now, y = 2x. Substitute y into equation (1).

4( 2x ) + 2x = 150

8x + 2x = 150

10x = 150

So; x = 150 / 10

x = 15

x= 15

y=2x————–eqn1

4y+2x=150

4(2x)+2x=150 {from eqn1}

10x=150

x=15

all wha we got to do is substitute the value of y in the given equation