Please help:( i don't understand this question Kendall’s benchmark test scores are the following: 89, 79, and 93. She has to take her fourth and final benchmark on June 6 th . She really wants to get an A in the class and in order to do so she must have an average of a 90. If Kendall’s teacher decides to count the final exam as two test grades, what would she need on the final test to make sure she gets an A?

Hey there!

The answer to your question is 94.5

We can use this equation, and solve: (we need to use "2x" because the score counts for 2 grades!)

(89 + 79 + 93 + 2x) / 5 = 90

(261 + 2x) / 5 = 90

261 + 2x = 450

2x = 189

x = 94.5

To check if it's right, we can add up all the scores, and divide by 5, and see if it's equal to 90. (Make sure to use 94.5 twice because it counts for 2 test grades!)

(89 + 79 + 93 + 94.5 + 94.5) / 5

450 / 5

90 ✔️

Hope it helps! Have a great day and good luck!

hello from mrbilldoesmath!

answer:

25x^2 + 90x + 84

discussion:

mn(x) = m(n(x)) = m( 5x + 9) =

(5x + 9)^2 + 3 =>

25x^2 + 90x + 9^2 + 3 =

25x^2 + 90x + 84                 (as 9^2 = 9*9 = 81)

which is the second choice

regards,  

mrb

p.s.   i'll be on vacation from friday, dec 22 to jan 2, 2019. have a great new year!

step-by-step explanation:

the answer is 128