Question

Complete the solution of the equation. Find the value of y when x equals -7.
-3x+6y=-21

Answer 1

how would you find the solution ?

Answer 2

Find the value of \(y\) when \(x = -7\)

How about you replace \(x\) with \((-7)\) in the equation? What does that give you?

Answer 3

-3x(-7)+6y=-21?

Answer 4

No, replace \(x\) with \((-7)\). You won't have any \(x\)'s present after you do that.

Answer 5

Oh whoops my mistake so theres no x after the -7,
-3(-7)+6y=-21 so you multiply ?
-3*-7=21

Answer 6

@jigglypuff314

Answer 7

mmm right so far I think?
-3(-7)+6y=-21 is right... then -3*-7=21 is true so
^simplifies to 21 + 6y = -21 <-- solve for y

Answer 8

subtract 21 from each side then divide by 6

Answer 9

so 6y=-42 so y=-7

Answer 10

subtract from which sides ?

Answer 11

the side with the 6y on it

Answer 12

21 + 6y = -21
-21 -21
6y = -42

Answer 13

then divide by 6 so y=-7

Answer 14

ok help me out with this one bro
Complete the solution of the equation. Findthe value of y when x equals 6.
4x+y=20

Answer 15

same idea :)
plug in 6 for x
to get 4(6) + y = 20 then solve for y

Answer 16

24+y=20

Answer 17

subtract 24 from the same side as y
y=-4

Answer 18

ok so first you
4(6)+y=20
24+y=20
ohhh ok i get your so
the answer is y=-4

Answer 19

yep :)

Answer 20

i thought you had to divide ?

Answer 21

only if/when there is a coefficient attached to the y
like if it was "2y" you would divide by 2
but since it's just " y " you don't have to :)

Answer 22

thanks guys this helped out big time !

Answer 23

glad we could help :)

Answer 24

Sorry I had to turn into a pumpkin in the middle, glad @jigglypuff314 finished the problem for you!