Solve each linear system using substitution please help?

Question

3x + y = -7 and -3x + 6y = 4

Answer 1

Well first solve one of the equations for Y or X:
In this case lets solve the first equation for Y:

3x + y = -7
y = -7 - 3x

Then substitute -7 - 3x in for y into the other equation:
-3x + 6y = 4
-3x + 6(-7 - 3x) = 4
-3x - 42 - 18x = 4
-42 - 21x = 4
-21x = 46
x = -46/21

Now substitue x in either equation to find y
Lets use: y = -7 - 3x
y = -7 - 3(-46/21) = -3/7

Answer 2

From first equation
y = -7 - 3x

Substituting this in the second equation
-3x + 6(-7 - 3x) = 4
-3x - 42 - 18x = 4
-21x = 46
x = - 46 / 21

Substituting this in first equation
y = -7 + 3(46 / 21)
y = -7 + 46 / 7
y = (-49 + 46) / 7
y = - 3 / 7

Solution is x = - 46 / 21 and y = - 3 / 7

Answer 3

y=-7-3x (1) remplace one in 2 -3x+6y= 4 (2) then we have
-3x + 6 ( -7-3x)=4
-3x -42-18x=4 y=-7-3x
y= -7-3(-46/21)
-21x=4+42 = -7 simplify 3 and 21
-21x=46 divided both side by -21 -7 +46/7 seek for comm
x=-46/21 then replace x to found y denominator
-49+46/7 all divided by 7 then
-3/7 that the answer for y

Answer 4

From first equation y = -7 - 3x Substituting this contained interior the 2d equation -3x + 6(-7 - 3x) = 4 -3x - 40 2 - 18x = 4 -21x = 40 six x = - 40 six / 21 Substituting this in first equation y = -7 + 3(40 six / 21) y = -7 + 40 six / 7 y = (-40 9 + 40 six) / 7 y = - 3 / 7 answer is x = - 40 six / 21 and y = - 3 / 7

Answer 5

3x + y = -7 ---(1)
-3x + 6y = 4 ---(2)

From equation (1) : y = -7 -3x ---- (3)

sub. (3) into (2)

-3x + 6(-7-3x) = 4
-3x - 42 - 18x = 4
-21x = 46
x = -2 4/21
For y, you sub. the value x
y = -7 - 3(-46/21)
= -3/7
Hope this helps you! =)

Answer 6

3x + y = -7
y=-7-3x

-3x + 6y = 4
-3x+6(-7-3x)=4
-3x-42-18x=4
-21x-42=4
-21x=46
x=46/(-21)=-2.1905

Answer 7

from 1st eq we get
y=-3x-7
put it 2nd eq
-3x+6(-3x-7)=4
-3x-18x-42=4
23x=-46
x=-2
then
y=-3(-2)-7
y=-1