10y + 20 is an equivalent expression
Answer:

Step-by-step explanation:
It is $6 more now than before...maybe you were looking for percent increase?
%change=100(final-initial)/initial
%change=100(10-4)/4=150% increase
The change is given by the difference between how much you paid and how much you actually had to pay. For example, if you pay with a $50 bill and you had to pay $13, your change will be
dollars.
In this case, we have

So, Gabriel's mistake was to leave the negative sign to the "-2" at the end of the expression, instead of flipping it to positive "+2" when subtracting it.
Answer: F=140
Step-by-step explanation:
720=(x-60)+(x-40)+(x-20)+130+120+110
720-130-120-110=3x-120
360=3x-120
360+120=3x
480=3x
480/3=x
160=x
F=160-20
Next problem
102+31+x=180
133+x=180
x=180-133
x=47