Question

Solve, using the substitution method.

y – 3x = 7
21 + 9x = 3y

Answer 1

A.
There is no solution.

B.
There are an infinite number of solutions.

C.
The solution is (1, 10)

D.
The solution is (28, 0)

Answer 2

Move the 3x:
y=3x+7
Now sub in:
\[\LARGE 21+9x=3(3x+7)\]
Distribute:
\[\LARGE 21+9x=9x+21\]
Simplify:
\[\LARGE 21=21\]
Which is a true statement so it infinitely many solutions

Answer 3

thank you, so B?

Answer 4

Yup!

Answer 5

Thanks!

Answer 6

You are very welcome