Question

Solve the system using addition. Use pencil and paper. Explain why the addition method is a good choice for solving the system. If you wanted to solve for x​ first, is the addition method still a good​ choice? Explain.

x-5.2y= -5.4
-x+4.3y=3.6

Answer 1

x = 5, y = 2

Explanation:

x - 5.2y = -5.4

+ (-x + 4.3y = 3.6)

-------------------------

-0.9y = -1.8

y = 2

x - 5.2(2) = -5.4

x - 10.4 = -5.4

x = 5

The addition (elimination) method is a good choice for solving this system because the x's are already opposites, and will cancel out when the two equations are added together. If one was to solve for x first, this method wouldn't be as good of a choice since it involves extra steps to eliminate the y's from the equation.