Question

Solve the system by substitution

Question 1)
X=2x
X-y=9

Question 2
Y= -3x
4x -2y= -20


Solve either or or both doesn’t matter

Answer 1

I think its:

Q1= x=(9+y)/2

Q2= x=(-20-6xy)/4

Explanation:

Q1)

X-y=9

2x-y=9

2x=9+y

x=(9+y)/2

Q2)

4x-2y=-20

4x-2(-3x)=-20

4x+6xy=-20

4x=-20-6xy

x=(-20-6xy)/4