Struggling on my review worksheet

Question

2x+7y=1

y=4x−8

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Is (4,8) a solution of the system?

Answer 1

the only solution is (2.1, 0.4) not (4,8)

just plug x=4 and y=8 into either equation. It is a solution to the 2nd equation, but not the 1st.

2x + 7y

2(4) +7(8)

=8+56

=64 which doesn't =1

y=4x-8

8=4(4)-8

8 =16-8 =8

but

y=4x +8

.4 = 4(2.1)-8

= 8.4 - 8

= .4

and

2(2.1) +7(.4)

= 4.2+2.8

= 7