Answer: this is just the first one
y = -3.5x + 2
subtract the 7x from both sides to get 2y = -7x + 4
divide by 2 to get rid of the 2 so you get y = -3.5 + 2
For the third the mistake was adding 3.
You're meant to subtract the 10x from both sides to get -3y = -10x + 6
Divide everything by -3 to get y = 3.3 - 2