Afriend bought 2 boxes and 8 notebooks for school, it cost him $11 he went back to the store the same day to buy school supplies for his younger brother. he spent $11.25 on 3 boxes of pencils and 5 notebooks. how much would 7 notebooks cost?

  $5.25

Step-by-step explanation:

If the friend tripled the first purchase and subtracted twice the second purchase, he would have the cost of 3·8-2·5 = 14 notebooks. 7 notebooks would cost half that amount:

  (3·$11 -2·11.25)/2 = $5.25 . . . . . cost of 7 notebooks

assuming you mean addition: addition and subtraction are reverse operations.

step-by-step explanation:

step-by-step explanation:

there is a formula i can give you:

it is r^2*n*sin(360/n) divided by 2 where r represents the "radius" and n is the number of sides.

plug them in:

(10sqrt(3))^2*6*sin(360/6) divided by 2

100*3*6*sin(60) divided by 2

900*sin(60)

900*sqrt(3)/2

450*sqrt(3)

approx is 779.4 cm^2