Solve: 4x + y = - 18 and x - y = - 7?

Question

Maybe you could explain me that. Step by step:)

Answer 1

from: 4x + y = - 18

we get that y = -18 - 4x

substitute in the second equation: x - y = - 7

and we get: x - (-18 - 4x) = - 7
so:
x + 18 + 4x = -7
5x = -25
x = - 5
so y= - 18 - 4(-5) = - 18 + 20
y=2

Answer 2

Use substitution to solve this.

x - y = -7
+ y = + y
-------------
x = y - 7 Now you know what x equals.

4x + y = -18
4(y-7) + y = -18 Substitute x in this equation.
4y-28+y = -18 Use distributive property
5y-28 = -18 Combine like terms
+28 +28
-----------------
5y = 10 Add 28 to both sides.
---- -----
5 5

y = 2 Divide by 5 both sides.

Take one of the equations and substitue in y to find x.

x - y = -7
x-2= -7
+2 +2
---------
x= -5

Answer is (-5, 2)

Answer 3

4x + y = - 18
y = - 18 - 4x put into second equation
x - (-18 - 4x) = -7
x + 18 + 4x = -7
5x = - 7 - 18
5x = - 25
x = - 25 / 5
x = - 5 put it in first equation
4( - 5) + y = - 18
- 20 + y = - 18
y = -18 + 20
y = + 2
therefor
x = - 5 and y = 2

Answer 4

4x+y= -18 assume this equation as A
x-y= -7 assume this equation as B

now add A and B
4x+y= -18
x-y= -7

it will be

5x= -25 (+y and -y will be calcelled)

then
x= -25/5
now x will be = -5

now substitute the value of x in either A or B
B will be more easier
-5-y= -7
-y= -2 (cancel the negatives)

y=2


ANSWERS are x= -5 and y=2

Answer 5

add both equations : u get 5x = -25 --> x = -5.
substitute in 1 eqn : y = -18 - 4x = -18 - 4(-5)
y = -18 + 20 = 2;

so, x = -5 and y = 2.

Answer 6

x = y -7 -----> #1

from #1
4(y - 7)+y= - 18
4y-28+y=-18
-24y=18 ( / -24)
y= - 3/4

and agian
x - y = -7
x - (-3/4) = -7
x = -7 -3/4= 31/4

Answer 7

4x + y = - 18
x - y = - 7----------ADD

5x = - 25
x = - 5

-20 + y = - 18
y = 2

x = - 5 , y = 2

Answer 8

4x+y=-18..............(1)
x-y=-7..............(2)
(1)+(2) gives:
5x=-25
x=-5. put in (2):
-5-y=-7
y=2.
Answer: (-5,2).