I assume you mean:
P=m/(1+rt) multiply both sides by (1+rt)
P(1+rt)=m perform indicated multiplication on left side
P+Prt=m subtract P from both sides
Prt=m-P divide both sides by Pr
t=(m-P)/(Pr)
I would first add 5 and 2 together, then multiply that by 3. Finally you would subtract the 1. After solving for what is inside the parentheses you would multiply it by 2 for your final answer.
2•(3(5+2)-1)
2•(3(7)-1)
2•(21-1)
2•(20)
40
ANSWER
See below
EXPLANATION
Part a)
The given function is

From the graph, we can observe that, the absolute maximum occurs at (-0.7746,6.1859) and the absolute minimum occurs at (0.7746,5.8141).
b) Using calculus, we find the first derivative of the given function.

At turning point f'(x)=0.

This implies that,



We plug this values into the original function to obtain the y-values of the turning points

We now use the second derivative test to determine the absolute maximum minimum on the interval [-1,1]


Hence

is a maximum point.

Hence

is a minimum point.

Hence (0,-6) is a point of inflexion