Question

PLEASE HELP! solve the system of equations
3x-4y=100
x/3+4y/3=100

Answer 1

look at the picture below
(a little bit shorter than first answer)

Answer 2

`\left \{ {3x-4y=100 \atop \frac{x}3+\frac{4y}3=100`

Let's use substitution to solve.
First, get one of the variables on its own side in both equations.


`\left \{ {3x=100+4y \atop \frac{x}3=100-\frac{4y}3`

Now, we want both of the equations to have the same value of x.
Let's multiply the bottom equation by 9 to accomplish this.


`\left \{ {3x=100+4y \atop 3x=900-12y`

Now we can set the right side of both equations equal to each other (substitution)


`100+4y=900-12y`

Let's solve for y.


`100+16y=900 \\ 16y=800 \\ \boxed{y=50}`

Now we can use
`y=25` in an earlier equation to find x.


`3x-4y=100 \\ 3x-4*50=100 \\ 3x-200 = 100 \\ 3x=300 \\ \boxed{x=100}`