Use Pythagorean theorem to find the missing length. (round to tenth if necessary) IS 11.7
8
7
64

11.7

Formula: a^2 + b^2 = c^2

so substitute the numbers like this:

10^2 + 6^2 = c^2

both 10^2 and 6^2 are perfect squares:

10 × 10= 100 and 6 × 6= 36

100 + 36= c^2

add:

100 + 36 =

136 = c^2

now in order to get rid of the squared, you put it into a radical:

√136 = √c^2

note: whatever you do on one side, you do to the other

it's easier to use the calculator for this so put √136 and you're gonna get 11.66

since it's asking you to round it to the nearest tenth:

11.66 = 11.7

sorry if the explanation is kinda long ✋ i tried explaining it better in the end but i failed

you have to find the same variables -3n - 5n so this would be -3n +(-5n) which equals -9n

$25 becasue a 10 increase would make it from 80 to 50