How do you solve the first problem? (about the geometric series, and finding the first term and common ratio)

First term = 5.

Common ratio = -3.

Step-by-step explanation:

Third term = a1 r^2 = 45. As r is an integer  3 or -3 is a possible value of r.

If r = 3 then the first term a1 = 45 / 9 = 5.

Substitute a1 = 5 and r = 3 into the formula for the sum of 7 terms which is given as 2735.  

Try r = 3:

S7  = 5 * (3^7 - 1) / (3 - 1) =   5465 so  r can't be  equal to 3.

Try r = -3:-

If r = -3 then a1 = 5 so

S7 = 5 * ((-3)^7 - 1) / (-3-1)  

= 5 *  547

= 2735 which is the value given.

So r = -3   and a1 = 5.

3.4 pizzas

step-by-step explanation:

given is a scatter plot showing number of pizzas sold during weeks for different issues of coupon

y represents number of pizzas sold and x number of coupons issued

y is marked verticaly and x horizontally

the trend line is given as

y =3.4x+43

this says that even when no coupon is issued pizzas sold will be 43

and rate of change of pizza sold for 1 unit of coupon = slope = 3.4

i.e. when x increases by 1 unit y increases by 3.4 units

hence for each additional coupon issued 3.4 pizzas more will be sold

what "following statement"?

step-by-step explanation: