Answer:
Use the app desmos is really good
To solve for x just isolate x by moving the other variables so....:
First add c to both sides
g+c= y+x
Subtract y from both sides
g+c-y= x
That should be your final answer (we cannot come up with an actual digit for x because there are no numbers in this equation we simply can make an equation for x)
240 each 10 percent is 30 calories multiply them by ten gets you 300
65÷455= 7
Hope this helps!