Question

Name the y value of the solution to the system of equations.

Use substitution:

-4x + y = 6

-5x - y = 21

Answer 1

you might have to set the two to equal each other
-4x+y=6
+4x +4x
---------
y=4x+6


then


-5x-y=21
+5x +5x
---------
-y=5x+21
y=-5x-21

Answer 2

then you could do this:

-5x-21=4x+6


since each end equals y. Then solve for x. Once you solve for x, plug the x value into one of the equations and solve for y ^^

Answer 3

x=−3

Answer 4

@DJBreezy does this make sense so far?

Answer 5

-5x-21=4x+6
+5x +5x
----------
-21=9x+6
-6 -6
---------
-27=9x
/9 /9
------
x=-3 \(\color{green}\checkmark\)

that's right :)

Answer 6

now we solve for y

-4(-3)+y=6
12+y=6
-12 -12
-------
y=-6

Answer 7

you can also check with the other equation

-5(-3)-y=21
15-y=21
-15 -15
-------
-y=6
y=-6

Answer 8

both equations yield y=-6

therefore, the value of y is -6. Do you understand?

Answer 9

so the answer is -6??

Answer 10

yes and thx

Answer 11

no problem :)