Question

What is the solution to X and Y in these equations 3x + 9y=60 and -3x + y=30

Answer 1

Answer:

x= -7 y=9

Step-by-step explanation:

3x +9y= 60 [1]

-3x +y=30 [2] rewrite this as the following:  y=30+3x

With equation [2] you substitute it into equation [1]

so it will now be: 3x+ 9(30 +3x) =60

3x+270 +27x=60

Group the like terms

3x+27x=60-270

30x=-210

x=-7

Use this answer into the same equation

So: 3(-7)+9y=60

-21 +9y=60

9y=60+21

9y=81

y=9