If f(x) = x2 − 81 and g(x) = x+9/x-9, find g(x) · f(x).

f(x) = x² - 81 = ( x+ 9)(x - 9) Difference of two squares

g(x) = x+9/x-9

g(x) . f(x) = x + 9/ x - 9 × (x+9)(x - 9)

= ( x + 9)(x +9)

= ( x + 9)²

= x² + 18x + 81

Hope this helps.

Since the numbers are "to the power", you expand it by writing out the number, multiplied with itself.

1). -5 x -5 x -5 x-5 x -5 x -5 x -5 That is -5^7 (It is multiplied by itself 7 times) =-78125

2). Same thing. 2/5 x 2/5 x 2/5 = 8/125