Please help. I will give a medal and fan. I need help with these 5 questions.

1)
m=5p+8
m=-10p+3

2)
h=6g-4
h=-2g+28

3)
y=x-2
2x+2y=4

4)
3x-6y=30
y=-6x+34

5)
7x-8y=112
y=-2x+9

Question

Please help. I will give a medal and fan. I need help with these 5 questions.

1) 
m=5p+8
m=-10p+3

2)
h=6g-4
h=-2g+28

3)
y=x-2
2x+2y=4

4)
3x-6y=30
y=-6x+34

5) 
7x-8y=112
y=-2x+9

anonymous · Answer

You can subtract the two equations to solve 1 and 2, and use substitution for the others.

anonymous · Answer

well i dont noe i am very weak in maths

stormswan · Answer

it says on my paper: Solve each system using substitution. Check your Solution.

stormswan · Answer

and I dont know how to do any of this, because I was sick and my teacher just gave me the homework. can someone please teach me how to do these?

anonymous · Answer

If you have to use substitution it would be easier to start with #3 then.

anonymous · Answer

You know that $y=x-2$, so you can substitute that into the second equation to get $2x + 2(x-2)=4$.

stormswan · Answer

ok but where does the y go then?

anonymous · Answer

$y$ was replaced in the substitution because you have to get rid of it so that you can solve for $x$. Once you find $x$ you can plug that value back into one of the equations to find $y$.

stormswan · Answer

oh, ok. so what do I do now that I have 2x+2(x-2)=4

anonymous · Answer

Solve for $x$.

stormswan · Answer

so i would use pemdas? right

anonymous · Answer

You always need to respect order of operations but in this case you'll want to distribute the 2 in $2(x-2)$ first.

anonymous · Answer

$$2x + 2(x-2)=4$$$$2x + 2x - 4 = 4$$$$4x=8$$$$x=2$$

stormswan · Answer

that sort of makes sense. how would I solve for y? @Richard_Feynman

anonymous · Answer

Plug the value of $x$ you found back into the original equation with $y$ and solve for $y$.

stormswan · Answer

I dont understand... sorry.

saifoo.khan · Answer

Try this: https://www.khanacademy.org/math/algebra/systems-of-eq-and-ineq/fast-systems-of-equations/v/systems-of-equations

anonymous · Answer

Look back at $y=x+2$. You know that $x = 2$, so $y = 2 + 2$.

stormswan · Answer

ok, but how would I solve that?

anonymous · Answer

How would you solve what? $y= 2 + 2$ trivially means that $y=4$.

anonymous · Answer

There's nothing else to solve in #3 now that you have $x$ and $y$.

stormswan · Answer

but I meant how would I show my work and how would I actually set it up and solve it.