I would use a proportion
51.03/88% = x/100%
Which is saying: if 51.03 is 88% of the number, what is 100% of the number
Cross multiply to get x=57.99
I believe it is 10 and however many zeros there are and there's 6 so if I'm not mistaken the answer is

.
Answer:
Step-by-step explanation:
X+2.6=1.7
x+12=7
x+12-12=7-12 (subtract 12 from both sides)
x=-5
Answer:
no x values repeat, so yes it is a function
Step-by-step explanation: