Question

Solve the system of equations

y=3x+30
y=8x
_______________________

x= ??

y= ??

Answer 1

x=6, y=48

Since both equations are set equal to y, set 3x+30=8x. Subtract 3x from each side, getting 5x=30. Divide by 5, so x=6. Then, just plug in 6 for x in any of the two equations, so y=48.

Answer 2

Lets get started :)


y = 3x + 30
y = 8x

Since y = both the equations, we can equate them

8x = 3x + 30 {Take 3x by subtracting to the other side in order to find the value of the variable)
We do minus, when we see plus

8x - 3x = 3x - 3x + 30
3x and -3x cancels out in the right hand side

5x = 30

Divide by 5 on either side to isolate x
We do division, when we see multiplication


`(5x)/(5) = (30)/(5)`
5 and 5 cancels out

x = 6

Now, we need to substitute x by 6 in order to find y
We can substitute in either equation, we will still get the same value

y = 8(6)
= 48

y = 3(6) + 30
= 18 + 30
= 48

x = 6 , y = 48