Answer: The tip is $17
Step-by-step explanation: You multiply $85 by .2 to get this answer.
Ooh, fun
geometric sequences can be represented as

so the first 3 terms are



the sum is -7/10

and their product is -1/125

from the 2nd equation we can take the cube root of both sides to get

note that a=ar/r and ar²=(ar)r
so now rewrite 1st equation as

subsituting -1/5 for ar

which simplifies to

multiply both sides by 10r
-7r=-2-2r-2r²
add (2r²+2r+2) to both sides
2r²-5r+2=0
solve using quadratic formula
for


so
for 2r²-5r+2=0
a=2
b=-5
c=2




so

or

use them to solve for the value of a


try for r=2 and 1/2

or

test each
for a=-1/10 and r=2
a+ar+ar²=

it works
for a=-2/5 and r=1/2
a+ar+ar²=

it works
both have the same terms but one is simplified
the 3 numbers are

,

, and
Answer:
$45.15
Step-by-step explanation:
When you are dealing with questions with percents in them—like this one—you have to turn the percent into a decimal. To make 7.5% into a decimal, you move the decimal point 2 spaces to the left. So, 7.5% is also 0.075.
Now, we have to use this formula for these types of questions:
x + x(y)= the price with tax (or markup)
So, we can substitute the variables.
42+42(0.075)=the retail price
42(0.075)=3.15
42+3.15=45.15
So, the retail price will be $45.15