Linear equations help?!

I am studying for a math test that is tomorrow.
There are a couple of equations that i don't really get.....
The division sign: ----

3a
---- + 4 =-1
2


x
4 - ----- = -1
7


x=y+1
3x-y=7


y=6-3x
x=2y-19


Thank you for helping me pass the maths test tomorrow:)

**** The second equation is meant to be 4 minus x over 7 equals minus one, sorry it wouldn't let me do it right.

3a/2 + 4 = -1
Multiply by 2.
3a + 8 = -2
Subtract 8 from each side.
3a = -10
Divide each side by 3.
a = -10/3

4 - (x/7) = -1
Multiply by 7.
28 - x = -7
Add x to each side.
28 = -7 + x
Add 7 to each side.
35 = x
So x = 35.

x = y + 1
3x - y = 7
Substitute y + 1 for x in the second equation, because the first equation tells us that it's equivalent.
3(y + 1) - y = 7
3y + 3 - y = 7
2y + 3 = 7
2y = 4
y = 2
Now substitute 2 for y in the first equation, and solve for x.
x = y + 1
x = 2 + 1
x = 3
Answer: x = 3 and y = 2

y = 6 - 3x
x = 2y - 19
Substitute 6 - 3x for y in the second equation.
x = 2(6 - 3x) - 19
x = 12 - 6x - 19
7x = 12 - 19
7x = -7
x = -1
y = 6 - 3x
y = 6 - 3(-1)
y = 6 - (-3)
y = 9
Answer: x = -1 and y = 9

I'll do two as examples for the other two !

3a/2 +4 = -1......get all numbers to one side and the variables to the toher.

To get rid of +4 on the LHS me subtract 4 from BOTH SIDES.

3a/2 +4-4= -1 -4

4-4=0. -1-4 = -5

3a/2 = -5 the variable is mulitplied by 3/2 so we need to turn this into, so we multiply by the inverse fraction

ie 3/2 inverse if 2/3

3/2 * 2/3 = 3*2 / 2*3 =6/6=1

3a/2 *(2/3) = -5 *(2/3)

a = -5*2/ = -10/3


x=y+1
3x-y=7

Using substitution.let y= x-1 from first equation.