how would you solve this linear equation?

Question

-x - 2y = 3
y= 2 - 4x

Answer 1

just solve for y

-x-2y=3
+x +x
-2y=x+3
/-2 /-2
y=-1/2x-3/2

y=2-4x
y=-4x+2


hope this helps =]

Answer 2

Just plug the second equation into the first one.

-x-2(2-4x) =3
-x-4+8x = 3
-x + 8x = 3 +4
7x =7
x =1

Plug into either equation
-1-2y =3
-2y =4
y = -2
or
y = 2 -4x
y =2 -4(1)
y = 2- 4
y =-2
Both check. The solution set is {1,-2}

Answer 3

equation 1: -x - 2y = 3
equation 2: y= 2 - 4x

since y is isolated in equation 2, substitute for y in equation 1.

-x - 2(2-4x) = 3
-x -4 + 8x = 3
7x = 7
x = 1

Now substitute for x in the first equation
-1 - 2y = 3
-2y = 4
y = -2

Substitute for both x and y in equation 2 to check
-2 = 2 - 4(1)
-2 = -2
checks

x = 1
y = -2

Answer 4

Values of y:
- x - 2y = 3
2y = - x - 3
y = (- x - 3)/2

Finding x:
2 - 4x = (-x - 3)/2
4 - 8x = - x - 3
7x = 7
x = 1

Finding y:
= 2 - 4(1)
= 2 - 4
= - 2

Answer: x = 1, y = - 2

Proof:
- (1) - 2(- 2) = 3
- 1 + 4 = 3

Answer 5

Solve for x in the first equation then substitute the value of x into the second equation. Now you have an equation with only y variables. Solve for y. Then substitute the value for y back into either equation and solve for x.