Question

Francine solves the system of equations using the linear combination method.

4x+3y=−1
3x−5y=4
Which steps would allow her to eliminate the x terms in the system of equations?


(A) Multiply 4x+3y=−1 by 4. Multiply 3x−5y=4 by 3. Add the resulting equations together.

(B) Multiply 4x+3y=−1 by 3. Multiply 3x−5y=4 by −4 . Add the resulting equations together.

(C) Multiply 4x+3y=−1 by 5. Multiply 3x−5y=4 by 3. Add the resulting equations together.

(D) Multiply 4x+3y=−1 by −4 . Multiply 3x−5y=4 by 3. Add the resulting equations together.

Answer 1

Answer

(B) Multiply 4x+3y=−1 by 3. Multiply 3x−5y=4 by −4 . Add the resulting equations together.

Explanation

There are 2 ways of solving simultaneous equation, substitution and elimination.

In elimination, we either eliminate x or y. For this question, we are eliminating x.

(4x+3y=−1  )× 3

(3x−5y=4 ) × -4

Then add the results as follows.

    12x + 9y = -3

+  -12x + 20y = -16

       0x + 29y = -19

29y = -19

y = -19/29