Question

Solve y= -2x + 9 y= 4x -3

Answer 1

y = -2x + 9

y = 4x - 3

y is isolated in both equations, thus you may set the expressions (-2x + 9) and (4x - 3) equal to each other and solve for x.

-2x + 9 = 4x - 3

Subtract 9 from both sides.

-2x + 9 - 9 = 4x - 3 - 9

-2x = 4x - 12

Subtract 4x from both sides.

-2x - 4x = 4x - 12 - 4x

-6x = -12

Divide both sides by -6.

-6x/-6 = -12/-6

x = 2

Substitute 2 for x into one of the original equations to find y.

y = 4x - 3 (given)

y = 4(2) - 3 (substitute)

y = 8 - 3 (multiply)

y = 5 (subtract)

Plug x- and y-values into original equations to check work.

5 = -2(2) + 9

5 = - 4 + 9

5 = 5

5 = 4(2) - 3

5 = 8 - 3

5 = 5

Answer:

x = 2 and y = 5; (2, 5).

Answer 2

Set the two equations equal to each other, because both equal y

-2x + 9 = 4x - 3

Isolate the x.

-2x (-4x) + 9 (-9) = 4x (-4x) - 3 (-9)

-2x - 4x = - 3 - 9

-6x = -12

Isolate the x. Divide -6 from both sides

-6x/-6 = -12/-6

x = 2

Place 2 for x in one of the equations

y = 4(2) - 3

Solve

y = 8 - 3

y = 5

x = 2, y = 5 is your answer

hope this helps

~Audiomachine