How to solve for x and y in y=-3/5x+7 and y=8x?

Answer 1

Since you've got two expressions for y as a function of x, put them equal to each other and solve for x:
-3/5 x + 7 = 8x
=> -3x + 35 = 40x
=> x = 35/43
Then substitute into one of the original equations to get y:
y = 8x = 8(35/43) = 280/43.

Answer 2

Before I begin my answer, I'll assume that in the first equation, 'x' is multiplying 3/5 and not just 5.
There are two equations and two unknowns. Since the two equations are linearly independent, you will have an answer. All you have to do is substitute y = 8x in the first equation; we get 8x = -3/5x + 7. Now we want 'x' on the left side; summing both sides of the equation by +(3/5)x, we have 8x + (3/5)x = 7. To add 8 to 3/5, we need to convert 8 to a fraction with 5 in the denominator; that would be 40/5. 40/5 + 3/5 = 43/5. Multiplying both sides by 5/43, we get x = 35/43. Once you have 'x', just substitute it in the second equation, y = 8*35/43 = 6.511 (I used a calculator for this last one).

Answer 3

y=-3/5x+7 and y=8x

you can either eliminate or substitute... substitute is a little easier in this case

substitute y=8x into y=-3/5x+7

8x=-3/5+7

43/5x=7

multiply each side by 5/43
that will make it
x=78/5

Answer 4

y=-3/5x+7
y=8x

8x= - 3/5x + 7
8(3/5x) = 7

24 7
--- =
5x

24= 35x
24/35 =x
-------------------

to find y:

24/35 * 8 = 192/35

Answer 5

plug the y=8x into the other one and solve from there and when you get what y equals plug it back in and solve for x. but dont take my word for it.

Answer 6

I am not going to spend a huge amount of time on this, since it is the weekend so if you don't understand, ask your teacher (or your kids if you are older)