Question

what is the value of "y" in the system of the following equations :
x=y+3
2x+3y=-4

Answer 1

substitute x=y+3 in 2nd equation, what u get ?

Answer 2

3x-3y=9 (first eq multiplied by 3)
2x+3y=-4
adding the above two eq we have
5x=5
or x=1
now
y=x-3
hence y=1-3=-2

Answer 3

If you substitute the x=y+3 into 2x+3y=-4, you get:
2(y+3) + 3y= -4
Multiply it out to get: 2y+6+3y=-4. Then, combine like terms.
2y+3y= 5y +6=-4
Now you have to solve this like a regular equation:
First, subtract 6 from bothsides to get:
5y+6=-4
-6 -6
--------------
5y= -10
Divide 5
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y= -2

Questions?

Answer 4

y=-2