Need help with substitution!! 9th grade

1) 2x+3=-1
5x-2y=-12


2) x+2y=10
3x-y=2


please show work

1.2x+3=-1 -------------> 2x = -4
5x-2y=-12
........................
2x = -4 multiply both sides by 5 to eliminate x
5x -2y = -12 multiply both sides by -2 to eliminate x
......................................…
5 [ 2x = -4 ] 5
-2 [ 5x -2y = -12] -2
....................................
10x = -20
-10x +4y = 24
....................................
4y= 4
y=1
then substitute the value of y to 5x-2y=-12 since it is the only equation with y variable
5x -2(1) = -12
5x -2 = -12
5x = -12 +2
5x = -10
so x= -2

2. x+2y=10 multiply both sides by -3 to eliminate x
3x-y=2
..........................
-3[x+2y=10]-3
3x -y =2
............................
-3x -6y = -30
3x -y = 2
...........................
-7y = -28
so y = 4

then substitute to either of the equation(since they both have variable y) to get the value of x

x+2(4)=10
x+8=10
x=10-8
so x=2

1) you want to get one variable by itself.
2x+3= -1
subract the 3 from both sides
2x = -4
divide by 2 on both sides
x =-2
now replace this into your second equation
5(-2)-2y = -12
multiply
-10- 2y = -12
add the 10 on both sides
-2y = -2
divide on both sides.
y = 1

cant do the last one.. have to go. hope this helps!

1)subtract the 3......2x=-4, divide by 2 .... x=2
5(2)-2y=-12, 10-2y=-12....... -2y=-22, divide by -2 ... y=11
Now you substitute x and y since you know what they are. Do the check. Try the second one by yourself it's really not that hard.

2

x+2y=10
2*(3x-y=2)

x+2y=10
6x-2y=4
7x=14
x=2
y=4

i must be to old i never had that in school sorry dear