Question

Which of the following systems of equations is an example of one where elimination is the best method?

Answer 1

(d)

Explanation:

Elimination is a good choice of solution method when the coefficient of a variable in one equation is a simple multiple of the coefficient of that same variable in the other equation. This is the case for the system in the last choice. (see attached)

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We can consider the alternatives:

(a) substitution for y would work well

(b) the solution is given, no solution effort is required

(c) substitution for y would work well

(d) elimination would work well.

3(2x +3y) +(-6x +y) = 3(18) +(12) . . . . . eliminates x (y=6.6)

(2x +3y) -3(-6x +y) = (18) -3(12) . . . . . . eliminates y (x=-0.9)