Think & Click: Elimination Method
Now, you try. Complete the Think & Click activity by looking at each problem below, thinking about it, and then clicking on the question to reveal the solution.
5x – y = 20
Multiply the second equation by 3 to get the y-coefficients so they are opposite.
2x + 3y = 8
15x – 3y = 60
Add the two equations together. Solve.
17x + 0y = 68
17x = 68
x = 4
Substitute this value into one of the original equations and solve for y.
2(4) + 3y = 8
8 + 3y = 8
3y = 0
y = 0
Solution: (4, 0)
3x + 2y = -7
Multiply the first equation by 2 and the second equation by 5 to get the y-coefficients so they are opposite.
4x – 10y = 16
15x + 10y = -35
Add the two equations together. Solve.
19x + 0y = -19
19x = -19
x = -1
Substitute this value into one of the original equations and solve for y.
3(-1) + 2y = -7
-3 + 2y = -7
2y = -4
y = -2
Solution: (-1, -2)
