So if I have the equations 3x-3y=-9 and 2x+9=9 solve for both x and y?
Mathematics · Middle School · Mon Jan 18 2021
Answered on
Given the numerical equation:
3x - 3y = -9
Can be written as,
3x - 3y + 9 = 0
2x + 9 = 9
Can be written as,
2x + 9 - 9 = 0
2x = 0
Solve for x and y.
Solution:
In order to solve for x and y, we simply equate the values into one single solution.
3x - 3y + 9 = 2x
Transpose 2x on the other side of the equation, hence we must take note that in transposing numbers, the sign changes.
= 3x - 2x - 3y + 9
= x - 3y + 9
Solve for x.
In order to solve for x, we need to transpose -3y and 9 to the other side of the equation.
x = 3y - 9
Solve for y.
In order to solve for y, we need to transpose -3y on the other side of the equation, and divide both sides by 3 in order to cancel out 3y, leaving behind y.
3y = x + 9
3y/3 = (x + 9)/3
y = ⅓x + 3
Final answer:
x = 3y - 9
y = ⅓x + 3