What's the end of infinity

to be In digits wite a equation about it​

If x + 10 = 70, what is x? a. 40 b. 50 c. 60 d. 70 e. 80

Evaluate the expression for the given value of the variable 2×(c2-5) for c=4

Ateacher brought a pack of 17 batteries . each calculator uses 3 batteries . how many calculator can the teacher fill with batteries