Jerry started doing sit-ups every day. the first day he did 15 sit-ups. every day after that he did 4 more sit-ups than he had done the previous day. today jerry did 65 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.

The first day Jerry did 15 sit-ups:

a0 = 15

The 2nd day he did 4 more sit-ups then the previous:

a1 = a0 + 4

The 3rd day he did 4 more sit-ups then the previous:

a2 = a1 + 4

a2 = a0 + 4 + 4

a2 = a0 + 4*4

the (n+1)-th day he did:

an = a0 + 4n

Today Jerry did 65 sit-ups means we have: an = 65 and we need to find n

a0 + 4n = 65

15 + 4n = 65

Now to solve

subtract 15 from both sides 

4n = 50

divide both sides by 4

n = 12.5

But I think this is counting the first day

Not counting the first day would be

4n = 65

n = 16.25

I guess that's the answer :)

the answer to this question is 3/19

step-by-step explanation:

region b will make the inequalities y < 2x + 1 and y > -x - 2 true ⇒ answer a

step-by-step explanation:

* lets study the graph and the inequality to solve the question

- the inequality y > -x - 2

∵ the form of the inequality is y > mx + c , m is the slope of the line

  and c is the y-intercept (the line intersect y-axis at point (0 , c)

∴ c = -2 that means the line intersect the y-axis at point (0 , -2)

∵ the sign of the inequality is >

∴ we shad the part over the line

  region a and b

- the inequality y < 2x + 1

∵ the form of the inequality is y > mx + c , m is the slope of the line

  and c is the y-intercept (the line intersect y-axis at point (0 , c)

∴ c = 1 that means the line intersect the y-axis at point (0 , 1)

∵ the sign of the inequality is <

∴ we shad the part under the line

  region b and c

∵ the common region between the two lines is region b

∴ region b will make the inequalities y < 2x + 1 and y > -x - 2 true