(ab - 9)(ab + 8)

Question

how do you foil this?

Answer 1

ab and ab are put together creating "a" squared and "b "squared Then you multiply (8*ab) and (-9*ab) which gives you +8ab and -9ab -9*8 which gives you a squared*b squared - 1 ab-72 or a squared b squared - 1ab-72. Sorry, but I have no idea how to do square numbers on the computer.

Nancy n.

Answer 2

Step 1: (ab-9)(ab+8)

Step 2: ab x ab +8 x ab -9 x ab -9 x 8

Step 3:  ab²  +8ab-9ab-72=

Step 4: ab² -ab-72

solved!!! that how you would solve it everything will continue as normal

Answer 3

Same way you would it "a" was a number instead of a variable:

(ab)(ab) + (8)(ab) - (9)(ab) - (9)(8)

a²b² - ab - 72