Math help!

Metal425

New Member
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7
Solve by substiution.

Will give mass loads of rep for correct answers.


1.
2x-3y=-14
3x-y=-7

2.
-3x+y=-3
2x-5y=-11

3.
2x+5y=4
x+5y=7

4.
x-5y=-3
4x-3y=5
 

Ghan

Administrator - Servers are fun
Staff member
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889
1.
2x-3y=-14
3x-y=-7

2x-3y=-14
2x=3y-14
x=(3/2)y-7

3((3/2)y-7)-y=-7
(9/2)y-21-y=-7
(7/2)y-21=-7
(7/2)y=14
7y=28
y=4

2x-3(4)=-14
2x=-2
x=-1

2.
-3x+y=-3
2x-5y=-11

-3x+y=-3
y=3x-3

2x-5(3x-3)=-11
2x-15x+15=-11
-13x=-26
x=2

-3(2)+y=-3
-6+y=-3
y=3

3.
2x+5y=4
x+5y=7

x+5y=7
x=-5y+7

2(-5y+7)+5y=4
-10y+14+5y=4
-5y+14=4
-5y=-10
y=2

x+5(2)=7
x+10=7
x=-3

4.
x=5y=-3
4x-3y=5

> x=5y=-3

Was that what you intended? Seems a bit strange to have two equals....
 

Ghan

Administrator - Servers are fun
Staff member
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889
x-5y=-3
4x-3y=5

x-5y=-3
x=5y-3

4(5y-3)-3y=5
20y-12-3y=5
17y=17
y=1

4x-3(1)=5
4x-3=5
4x=8
x=2
 

w/e

Boaroceraptorasaurus-Rex
Reaction score
274
You could've just google'd "system of equation" calculator, or used matrices.
 

Azlier

Old World Ghost
Reaction score
461
I got the idea that we were supposed to do his homework :eek:
 

Zakyath

Member
Reaction score
239
I got the idea he has got a test coming up and is not sure how to solve this sort of problems...
 
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