Question

Is anyone willing to help with some 8th grade math?

Answer 1

Sweet, we got some invisible mathematics on here:)
lol, what is your question ?

Answer 2

Consider the following pair of equations:

y = –2x + 8
y = x – 1

Explain how you will solve the pair of equations by substitution. Show all the steps and write the solution in (x, y) form.

Answer 3

I have 7 questions

Answer 4

Lets do one question per post. Is that okay?

Answer 5

okay

Answer 6

so we will go straight to your problem (that you posted).
In front of you is the system of equations, and the solution is the intersection point.

Which methods have you learned/like substitution, elimination, (graphing - if that is permitted) and/or matrix?

Answer 7

I would do a direct substitution in this case.

Answer 8

I dont know how to do that

Answer 9

\(\large\color{black}{ \displaystyle y=-2x+8 }\)
\(\large\color{black}{ \displaystyle y=x-1 }\)

so you can use your second equation.
it tells you that y is same thing as x-1

so, instead of saying
\(\large\color{black}{ \displaystyle \color{red}{y}=-2x+8 }\) ,

you can write:
\(\large\color{black}{ \displaystyle \color{red}{x-1}=-2x+8 }\)

Answer 10

Fair enough ?

Answer 11

okay so I would type x - 1 + -2x +8 ?

Answer 12

yes (don't leave your signs out though)

\(\large\color{black}{ \displaystyle \color{red}{x-1}=-2x+8 }\)

Answer 13

can you solve for \(\large\color{black}{ \displaystyle x}\) in this equation ?

Answer 14

I dont know how to? I was gone during this lesson..

Answer 15

\(\large\color{black}{ \displaystyle x-1=-2x+8 }\)

\(\small\color{black}{ \displaystyle \bullet }\) Add \(\normalsize\color{black}{ \displaystyle 2x }\) to both sides.
\(\small\color{black}{ \displaystyle \bullet }\) Add \(\normalsize\color{black}{ \displaystyle 1 }\) to both sides.
\(\small\color{black}{ \displaystyle \bullet }\) Divide by \(\normalsize\color{black}{ \displaystyle 3 }\) on both sides.

Answer 16

lets start with adding 2x to both sides.

YOU HAD:
\(\large\color{black}{ \displaystyle x-1=-2x+8 }\)

NOW ADDING:
\(\large\color{black}{ \displaystyle x-1\color{blue}{+2x}=-2x+8\color{blue}{+2x} }\)


what will you get after doing this, can you tell me?

Answer 17

x-3x=8x?

Answer 18

I apologize, but you aren't showing enough background for solving this problem. I would strongly advise to get assistance with (and so respectively):

1) What "like terms" are and how to add them.
2) Substitution and Elimination methods of solving a system of equations.

to proceed without knowing at least the #1, would be irrational.