Question

Please help, I need to write a two-column proof?

Given: 7y = 8x - 14; y = 6
Prove: x = 7
@Hero

Answer 1

Input x = 7 and y = 6 into the equation

Answer 2

7(6) = 8(7)

Answer 3

but I need to write the steps and stuff

Answer 4

Well. You can start it off by working it out like this:

7y = 8x - 14; y = 6
So,

7(6) = 8x - 14
42 = 8x - 14
42 = 8(7) - 14
42 = 56 - 14
Then, 56 - 14 = 42.

So, 42 = 42

That's your proof. :)

Answer 5

Replace x for a number like finding out a simple variable by trying different numbers, but 7 it your answer because it fits into the equation.

Answer 6

So like if I was going to write it out
7y = 8x - 14 ; y = 6 Given
7(6) = 8x - 14 Substitution Property of Equality
42 = 8x - 14

What would the next step be?

Answer 7

Plug in x for a number until you get the correct one, which is 7. It's sorta similar to finding an answer for a simple equation with a variable in it, trying different numbers until you have the correct one.

Answer 8

It's asking me for the properties though, see like the substitution property, I just don't know what property that would represent

Answer 9

But here is another way of doing it, I'll start off from when you asked what the next step would be.

Answer 10

42 = 8x - 14
Add 14 to both sides.
42 (+14) = 8x - 14 (+14)
56 = 8x

Now plug in x with a number.
x = 6 won't work because it'll equal 48. But x = 8 won't work either because it'll equal 64. x = 7 because it fits, and it finishes the equation:

56 = 8(7)
56 = 56

Answer 11

You have 2 sets of proof there. :)

Answer 12

So for the next step is that the addition property

Answer 13

o.o

Answer 14

Uh. o.o What do you mean? :u

Answer 15

i know how to solve the proof but i need to figure out the properties lol its ok i can probably find it in the textbook :P thanks for helping though i wouldnt have solved it right

Answer 16

Okay, lol. You're welcome. :D

Answer 17

Yay. We fanned each other. xD

Answer 18

xP