Robert stands a top eight 1380 foot hill. He climbs down, which is the bottom of the hill in 30 minutes. What is Roberts average rate of elevation change in feet per minute?

the answer is  

a.

4,624π mm2

step-by-step explanation:

system of linear equation

step-by-step explanation:

as given in the data

a= 20 , b= -12

let us suppose that it is a straight line equation

now we know the formula for the system of linear equation

b= ma + c )

here m is slope of a straight line which is equal to formula

m=   (ii)

and here c is a constant

now putting the value of a and b in equation (ii)

m=

m=

putting the value of a,b and m in equation (i) gives us

-12 = + c

-12=-12 + c

adding 12 to both sides

-12 +12 = -12 +12 +c

0 =c

or c=0

as the value of the constant is zero which gives us that it is a linear equation and this order pair satisfies the system of linear equations.

question 1: step-by-step explanation:

1/4 of 84 = 84÷4= 21