Algegra Hw help!?

Question

solving system of linear equations.

1.y=2x+1
3x-4y=1

2.5x-6y=23
x=6-3y

3.x+y=1
2x-3y=8

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

5.y-3x=5
3(x+1)=y-2

6.2y=1-4x
2x+y=0

7.2y=6-3x
1/2x+1/3y=3

8.2x=10-5y
1/5x+1/2y=1

9.x+y=200
0.05x+0.06y=10.50

10.2x+y=300
1/2x+1/3y=80

11.y=3x+1
y=3x-7

12.2x+y=9
4x+2y=10

13.1/2x-1/3y=12
1/4x-1/2y=1

14. 0.05x+0.1y=10
0.06x+0.2y=16



thank youuuu =)

Answer 1

That's way too much work for one question. If you want lots of answers and people working on your questions, you should break that up into at most 3 problems per question.

Generally, how you solve these is to place one of the equations in terms of x or y, and replace that value in the second equation.

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For example:

1.
y=2x+1
3x-4y=1

The first equation is already in terms of y, so replace "y" with "2x+1" in the second one:

3x - 4y = 1
3x - 4(2x + 1) = 1
3x - 8x - 4 = 1
-5x = 5
x = -1

Now use x=-1 in either original equation to solve for y:

y = 2x + 1
y = 2*(-1) + 1
y = -2 + 1
y = -1

The solution is x=-1 and y=-1.

==========================
Another example:
10.
2x+y=300
1/2x+1/3y=80

Solve the first equation for y:

2x + y = 300
y = 300 - 2x

Now replace "y" with "300 - 2x" in the second one:

1/2x + 1/3y = 80
1/2x + 1/3 (300 - 2x) = 80
1/2x + 100 - 2/3x = 80
20 = (2/3 - 1/2) x
20 = (1/6) x
x = 120

Now that you know x, go back to either original equation and replace x with that value:

2x + y = 300
2(120) + y = 300
240 + y = 300
y = 60

The solution to #10 is x=120 and y=60.

This one is more complex, so you can check the answers with both original equations:

2x + y =? 300
2(120) + 60 =? 300
240 + 60 =? 300
300 = 300

1/2x + 1/3y =? 80
1/2(120) + 1/3(60) =? 80
60 + 20 =? 80
80 = 80

Answer 2

I think you need do your own homework. Open your books and start doing some problems.

Answer 3

Its too long. No thanks
If I were you, split this into 2

Answer 4

Maybe you should be more worried about your spelling class.