Question

a. Multiply 7/4 X 9/10 and explain all your steps.b. Multiply n/(n-3) X 9/(n+3) and explain all your steps.c. Evaluate your answer to part (b) when n=7 . Did you get the same answer you got in part (a)? Why or why not?

Answer 1

A) Part A asked to multiply

Concept:

`(a)/(b)*(c)/(d)=(a* c)/(b* d)=(ac)/(bd)`

By applying the concept, we will have

`\begin{gathered} (7)/(4)*(9)/(10) \\ =(7*9)/(4*10)=(63)/(40) \end{gathered}`

Hence,

The answer to part A is = 63/40

Part B:

The part b asked to multiply

`(n)/((n-3))*(9)/((n+3))`

By applying the concept above, we will have

`\begin{gathered} (n)/((n-3))*(9)/((n+3)) \\ =(n*9)/((n-3)(n+3)) \\ =\frac{9n}{n(n+3)_{}-3(n+3)} \\ =(9n)/(n^2+3n-3n-9) \\ =(9n)/(n^2-9) \end{gathered}`

Therefore,

The answer to the multiplication of part B is

`(9n)/(n^2-9)`

Part C:

Evaluate your answer to part (b) when n=7

Substitute the value of n=7 in the expression below

`\begin{gathered} (9n)/(n^2-9),n=7 \\ =(9(7))/(7^2-9) \\ =(63)/(49-9) \\ =(63)/(40) \end{gathered}`

The answer to part c is = 63/40

The answer is the same as the answer gotten in part a BECAUSE ON SUBSTITUTING THE VALUE OF n=7 IN THE ANSWER IN PART B the same answer was gotten..