Solve, using the substitution method.
y – 3x = 7
21 + 9x = 3y

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)

Respuesta :

The answer is B

let me show my answer

-3x+y=7;9x+21=3y

Solve -3x+y=7 for y

Add 3x to  both sides

-3x+y+3x=7+3x

y=3x+7

Substitute 3x+7 for y in 9x+21 =3y

9x+21=3y

9x+21=3(3x+7)

Simplify both sides of the equation

9x+21=9x+21

Add -9x to both sides

9x+21+-9x=9x+21+-9x

21=21

Add -21 to both sides

21+-21=21+-21

0=0

Answer : B , Infinitely many solutions


I hope that's help !

Have a great day !




Answer:the answer is There are an infinite number of solutions.

Step-by-step explanation:took the test and got it right