y=-3+21 2x - 7y = -9?

Question

y = -3x + 21
2x - 7y = -9

Answer 1

1)y=-3x+21
2)2x-7y=-9 . substit. 1) into 2) then you has : 2x-7(-3x+21)=-9 =>23x=147-9 , 23x=138, x=6.put x=6 in 1)., then y=21-18=3.the solution is (6,3). END!

Answer 2

First: use substitution > y = -3x + 21 and replace it with "y" in the second equation:

2x - 7(-3x + 21) = - 9
2x - 7(-3x) - 7(21) = - 9
2x + 21x - 147 = - 9
23x - 147 = - 9

Second: add 147 to both sides (opposite side means opposite sign):

23x - 147 + 147 = -9 +147
23x = 138

Third: solve for "x" by keeping it on one side and dividing both sides by 23:

23x/23 = 138/23
x = 6

Next: take 6 and replace it with "x" in the first equation and solve for "y">>>

y = -3(6) + 21
y = -18 + 21
y = 3

(6, 3)

Answer 3

2x - 7 (-3x + 21) = -9
2x + (-7)(-3x + 21) = -9
2x + 21x + -147 = -9
2x + 21x + -147 + 147 = -9 + 147
23x = 138
23x / 23 = 138 / 23
x = 6

Plug the X value back into one of the original equations.
y = -3(6) + 21
y = -18 + 21
y = 3

ANS:
x = 6 & y = 3

Answer 4

Solve the system by using substitution.

2x -7(-3x + 21) = -9
distribute the -7
2x +21x - 147 = -9
23x - 147 = -9
23x = 138
x = 138 / 23
then use that value to solve for y
y = - 3x +21

Answer 5

X=6, Y=3

You substitute -3+21 in for y in the second problem so you get: 2x-7(-3x+21)=-9
2x+21x-147=-9
23x=138
x=6
then you pulg 6 in for x in either equation and get y=3.

Answer 6

i) y = -3x + 21
ii) 2x - 7y = -9

Subst i) into ii)

2x-7(-3x+21)=-9
2x+21x-147=-9
23x=138

therefore x=6

Substitute this back into i)
y=-18+21

Therefore
y=3

I hope that is of some assistance :-)

Answer 7

y=-3x+21
2x-7y=-9
-> y=-3x+21
-7y=-2x-9
-7(-3x+21)=-2x-9
21x-147=-2x-9
21x+2x=147-9
23x=138
x=6
y=-3*6+21=3
Answer :x=6,y=3

Answer 8

y=-3x+21...1
2x-7y=-9.....2
substitute 1in 2
2x-7[-3x+21]=-9
2x+21x-147=-9
23x=138
x=6
y=-18+21
=3

Answer 9

x= 6
y= 3