Jerry started doing sit-ups every day. The first day he did 13 sit-ups. Every day after that he did 4 more sit- ups than he had done the previous day. Today Jerry did 57 sit-ups. Write an equation that could be solved
to find the number of days Jerry has been doing sit-ups, not counting the first day. Let n represent the
number of days.
An equation that can help Jerry to find the number of days he has been doing sit-ups is given by

-14 is the answer

hope this : ))

x = ±sqrt(10)

step-by-step explanation:

5 - 2x² = -15

subtract 5 from each side

5-5 - 2x² = -15-5

-2x^2   = -20

divide by -2 on each side

-2x^2   /-2= -20/-2

x^2 =10

take the square root on each side

sqrt(x^2 )=±sqrt(10)

x = ±sqrt(10)

check:

5 - 2x² = -15

+sqrt(10)

5 - 2(sqrt(10))² = -15

5 -2(10) = -15

5 -20 = -15

-15 = -15

-sqrt(10)

5 - 2(-sqrt(10))² = -15

5 -2(10) = -15

5 -20 = -15

-15 = -15

4

step-by-step explanation:

im pretty sure it's 4 beacsue 8/2 equals 4