Question

9x +3y = -45
2x - 3y = -21

Answer 1

To solve this you need to first get one of the variables (x or y) by itself on of the sides.

Hint: 9x + 3y = -45 simplifies to 3x +y = -15

Answer 2

Add the two equations in order to eliminate the y variable:

9x+3y = -45
2x-3y = -21
-------------- add
11x=-66
x=-6 The problem is over half done.

Answer 3

Now substitute this newly found value of x in the second equation
2(-6) -3y = -21
-12 - 3y =-21
-3y= -21 +12
-3y = -9
y = 3 Now the problem is solved, x=-6
y=3