Answer: 0.1 or 
Step-by-step explanation:

= 
Answer:
y=3x+5
Step-by-step explanation:
I think that this is what they mean...
y=mx+b
y=3x+b
y=3x+5
plug in #s
5=15+5
5=20 no
Answer: 90
Step-by-step explanation:
45.5-.5=45
45^2=90
It all depends on the importance of the variable its self. Its important to solve it so you know what the variable is and its important to solve one at a time because its impossible to solve a variable completely if you have two of them