Question

Solve the following system of equations using elimination:
3x - 4y = 8
10x + 5y = 45


A. (-4, -1)
B. (3, 3)
C. (4, 1)
D. (8, 4)

Answer 1

Multiply the first equation by 10 and the second by -3,
\[\begin{cases}30x-40y=80\\
-30x-15y=-135\end{cases}\]Now, sum the equations,
\[-55y=-55\Rightarrow y=1\]Now, you can use again elimination, or simply use the first equation and substitute the y value obtained. Then solve for x, and you will obtain x=4. So the solution is (4,1).

Answer 2

Thank You so much! John

Answer 3

;)