Maths Homework Help! 10 Points!
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Maths Homework Help! 10 Points!

[From: ] [author: ] [Date: 11-09-14] [Hit: ]
(b)To cancel out x to find y, we need to multiply (a) by -3 and multiply (b) by 2. This is because once weve done that. The x values will be -6x and 6x, which cancel out so you can find y. :D(a) x -3-6x + -3y = -24 .......
x = 5

Finding y, which is a bit more difficult.

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

To cancel out x to find y, we need to multiply (a) by -3 and multiply (b) by 2. This is because once we've done that. The x values will be -6x and 6x, which cancel out so you can find y. :D

(a) x -3

-6x + -3y = -24 ....(c) New equation can be called (c)

(b) x 2

6x + 8y = 14 .... (d) New equation can be called (d)

Add (c) and (d)

-6x + -3y + 6x + 8y = -24 + 14
-3y + 8y = -10 The x values cancel out so now you can find y (-6x +6x = 0 aka cancels out)
5y = -10
y = -10/5
y = -2

------------------------> x = 5 and y = -2


Hoped this helped! :D

-
step 1 - times the 1st sum by 4
8x+4y=32
2 - then take subtract the bottom values from the top ones
(8x+4y=32) - (3x+4y=7) = 5x=25
5x= 25 so x=5
3 - substitute this into one of the the equations
10+y=8 (the 10 is the 2x)
take the 10 out of both sides - so y= -2
so finally x=5 and y= -2

-
2x+y = 8 ------------- (i)
3x+4y = 7 ------------- (ii)

Multiply eq. (i) by 3 and eq (ii) by 2 you'll get

6x+ 3y = 24 -------- (iii)
6x+ 8y = 14 -----------(iv)

Subtracting eq. iii from iv we will get
5y = -10
=> y = - 2
using this in eq (i)
x= 5

So x= 5, Y= - 2

-
solve the system using substitution...

2x + y = 8

y = 8 - 2x

so,

3x + 4(8 - 2x) = 7

3x + 32 - 8x = 7

- 5x = - 25

x = 5
y = - 2

check.


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

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

----
x=-3y
and
y=3x
12
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