The total cost c(x) of hiring a dump truck and an operator is described by the function c(x)=300+31x-3.90x^2 , where x is the number of hours worked. Find the number of working hours if c(x)=$220.

l.jnl.j/n.m,lm,

step-by-step explanation:

3

step-by-step explanation:

divide 13.5 by 9 to get the scale factor. it equals 1.5

2 * 1.5 = 3

option c is correct.

step-by-step explanation:

the rule regarding the sides of triangle is:

(length of longest side)^2 = square of sum of other two sides.

the sides given are:

6, 10 and 8.

applying the rule we will get:

(10)^2 = (6)^2 + (8)^2

100 = 36+64

100 = 100

so, her answer is incorrect.

no, she should have added 6^2 and 8^2 and compared that to 10^2.

so, option c is correct.