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)

Question

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)

danjs · Answer

solve the first equation for y

y = 3x + 7

danjs · Answer

place that y into the second equation

danjs · Answer

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

twizttiez · Answer

I think B

danjs · Answer

i didnt solve it , idk

anonymous · Answer

So, from where he left off, distribute the 3out

anonymous · Answer

You'll get 21+9x=9x+21

twizttiez · Answer

y – 3x = 7

y – 3x+3x = 7+3x

y + 0x = 3x + 7

y + 0 = 3x + 7

y = 3x + 7

Therefore infinite number of solutions

anonymous · Answer

That's the exact same line isn't it?

anonymous · Answer

Good job. It's the exact same line, therefore there are an infinite number.

twizttiez · Answer

YAY!

danjs · Answer

It would be infinite solutions because the second equations is a constant scalar multiple of the first (-3)

twizttiez · Answer

Could you help with one more?

anonymous · Answer

Sure!