Question

Select the best possible first step to solving the system by first eliminating the y variable.

4x – 5y = 4
3x + 2y = –20

A. None of the above
B. Multiply the first equation by 2 and multiply the second equation by 5.
C. Multiply the first equation by 2 and multiply the second equation by –5.
D. Multiply the first equation by –2 and multiply the second equation by 5.

Answer 1

B

Answer 2

\[4x-5y=4 \rightarrow \times2\]

Answer 3

\[3x+2y=-20\rightarrow \times5\]

Answer 4

B. Multiply the first equation by 2 and multiply the second equation by 5.

4x – 5y = 4
3x + 2y = –20
--------------
2*(4x – 5y = 4 )
5*(3x + 2y = –20)
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8x – 10y = 8
15x + 10y = –100

Answer 5

eliminate the y \[-10y +10y\]

Answer 6

yeah

Answer 7

8x – 10y = 8
15x + 10y = –100
----------------------
23x=-92

Answer 8

so the y can be eliminated

Answer 9

thus y is eliminated

Answer 10

and x=-92 div 23

Answer 11

b is right