4d + 7 = 13
Is this an equation or an expression?

This is an equation

Step-by-step explanation:

i think an equation bc of the equal sign

2.   2 3/5.

3.   2 1/2.

step-by-step explanation:

6 - 3 2/5

= 6 -   17/5

= 30/5 - 17/5

= 13/5

= 2 3/5 (answer).

5 1/4 - 2 3/4

= 21/4 - 11/4

= 10/4

= 2 1/2 (answer).

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