Maths Homework Help! 10 Points!

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| 2x+y=8
| 3x+4y=7
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How much is x? And how much is y? Please help me and explain!!!!

There so many ways to solve it.
The easiest way is to find y in function of x and replace it in the second equation.
2x + y = 8 ===> y = 8 - 2x
now in the second equation u replace y by 8 - 2x
3x + 4 * ( 8 - 2x ) = 7
3x + 32 - 8x = 7
-5x = -25
x= 5
then u know that y = 8 - 2x which means that y = -2

This is what's called a simultaneous equation. You use the information given to you in both equations to find x and y.
There are lots of ways to solve it, but the easiest way I think is as follows:

1) make the equations both equal zero

2x+y-8=0
3x+4y-7=0

2) now that they both equal zero, they equal each other too

2x+y-8=3x+4y-7

3)now you can cancel the x's and the y's off both sides of the equation by moving them around the equals sign (bring all your y's to one side and all the x's to another)

x=-3y -1

4) then substitute the above equation for x and solve for y

2(-3y -1) +y = 8
=> -6y -2 + y=8
=>-5y=10
=> y=-2

5) then substitute y=-2 into your original equation

2x-2=8
2x=10
x=5

so, x=5 and y=-2

Ok, so finding the values of x and y in stimulous equations.
Lets call each of the equations a and b.

2x+y=8 ....(a)
3x +4y = 7....(b)

What you have to do is make the equation so that either y or x is cancelled out (if you're finding x, cancel y out, and vise versa).

Finding x.

To cancel out y to find x you multiply equation (a) by -4, which gives you:

-8x+-4y=-32 ... (c) We'll call the new equation (c)

Now (b) + (c)

3x + 4y + -8x + -4y = -32 + 7
3x + -8x = -25 The y values cancel out (4y + -4y = 0 aka cancels)
-5x = -25
x = -25/-5