(X-5)(X+6)
Expand and simplify

Step-by-step explanation:

(x - 5)(x + 6) = x *(x + 6) - 5*(x + 6)

                   =x * x + 6 *x + x*(-5) + 6*(-5)

                    = x² + 6x - 5x - 30    {Combine like terms}

                    = x²  + x - 30

0.3716

Step-by-step explanation:

"OR" means "+" and "AND" means "*"

This is true for probability problems like this.

We want "the probability of getting someone in the 18 dash 21 age bracket or someone who refused to respond."

We need the probability of getting someone in the 18 dash 21 age bracket

We also need the probability someone who refused to respond

Then ADD both, [since "OR"]

Now,

Out of 366 people, 80 are from 18-21 bracket, so

the probability of getting someone in the 18 dash 21 age bracket = 80/366

Also,

Out of 366 people, (31+25)=56 refuse to respond

the probability someone who refused to respond = 56/366

the probability of getting someone in the 18 dash 21 age bracket or someone who refused to respond = 80/366 + 56/366 = 136/366 = 0.3716