Solving by substitution

This is giving me fits!!

3x + 8y = 7
-4x + y = 14


can one of you brilliant people help me with this one also...Id soo apprieciate!!

you must rearrange the second equation to y = 14 + 4x. The just sub it into the first equation so:
3x + 8(14 + 4x) = 7
3x + 112 + 32x = 7
35x = -105
x= -3

now that you have x= -3, sub x = -3 back into one of the first equations ( y= 14 + 4(-3) =2) therefore y = 2

In order to solve by substitution, set both equations equal to y or to x (take your pick, I will use y). First, for 3x + 8y = 7, divide throughout by 8, resulting in 3/8x + y = 7/8. Then, subtract 3/8x from both sides of the equation, resulting in y = 7/8 - 3/8x. Then, for the second equation, simply add 4x to both sides, resulting in y = 14 + 4x. Now, since both equations are equal to y, set them equal to each other, i.e., 14 + 4x = 7/8 - 3/8x. Now that there are only x terms, simplify the equation and determine your x value. Then, plug your x back into either 3x + 8y = 7 or -4x + y = 14 to determine your y values.

add 4x to both sides of the bottom equation so you get y= 4x+14. now you know what y equals so plug in (4x+14) where the y is in the top equation so the equation is 3x + 8(4x+14) =14. distribute the 8 so the equation becomes 3x+ 32x + 112=14. solve from there.

y=14+4x
substitute in the top -> 3x+8(14+4x)=7
3x+112+32x=7
35x=-105
x=-3
so y=14-12=2