Question

Could someone help me, please

Answer 1

Q1: No solutions

Q2: x=2, y=-2

Q3: x=1, y=4

Explanation:

Q1: Found out 0y = 18 which is impossible therefore no solution.

Q2:

In the first equation:
`2x - 4y = 12`

Let's express x in terms of y by changing the subject. Follow my steps.

`2x = 12+4y`

`x = (12+4y)/(2)`

Now let's put the x above into the second equation:
`-14x-4y=-20`

It becomes:
`-14((12+4y)/(2))-4y=-20`. Follow my steps.

`-7(12+4y)=-20+4y`

`-84-28y=-20+4y`

`-32y=64`

`y=-2`

Put y = -2 into the first equation:

`2x-4(-2)=12`

`2x+8=12`

`2x=12-8`

`2x=4`

`x=2`

Q3:

Multiply the first equation by 3 and the second equation by 7, so that both are 21x.

1st equation:

`3(7x-3y)=3(-5)`

`21x-9y=-15`

2nd equation:

`7(3x+2y) = 7(11)`

`21x+14y = 77`

We can now substract the 2nd equation with the 1st equation so that both 21x cancels out and only the variable y remains.

`21x-9y-(21x+14y)=-15-77`

`21x-9y-21x-14y=-92`

`-23y=-92`

`y=4`

Put y = 4 into the second equation to find x.

`3x+2(4)=11`

`3x+8=11`

`3x=11-8`

`3x = 3`

`x=1`