2007-06-12 03:55:46 · 13 answers · asked by mszbronx 2 in Science & Mathematics ➔ Mathematics
9I^2 - 27I + 27I - 81
= 9I^2 - 81
2007-06-12 04:01:06 · answer #1 · answered by Math Stud 3 · 0⤊ 0⤋
31+9=40 and 31-9=22 Multiply 40 and 22 and the answer is 880
2007-06-12 11:00:45 · answer #2 · answered by ewortham29 1 · 0⤊ 0⤋
40 X 22 = 880
2007-06-12 11:03:12 · answer #3 · answered by Nick 2 · 0⤊ 1⤋
Simple (3I)^2 - 81 = -9 - 81 = - 90
2007-06-12 11:00:51 · answer #4 · answered by jaime r 4 · 0⤊ 0⤋
are those l's or are they i's. Also if they are i's that means the square root of -1. i'll do both
if it is just a variable (with a value that is real)
This is a foil problem
Multiply the first term in each parenthetical group
9L^2
Then, add the the product of the outside terms
-29L
Then, add the product of the inside terms
+29L
Then add the product of the last term
-81
this gives you a product of...
9L^2-29L+29L-81
Combine like terms and
9L^2-81
Now, if you were dealing with i, then your product is
-9-81
or -90
This is acheived the same way
2007-06-12 11:03:20 · answer #5 · answered by Wastedmilkman61 3 · 1⤊ 0⤋
Is i the complex no. i? If so:-
(3i + 9).(3i - 9)
= 9i² - 81
= 9 x (-1) - 81
= - 9 - 81
= - 90
2007-06-12 11:01:49 · answer #6 · answered by Como 7 · 1⤊ 0⤋
31^2 -9^2
2007-06-12 10:58:35 · answer #7 · answered by mimi 3 · 0⤊ 1⤋
(31+9)(31-9)=40(22)=880
2007-06-12 11:02:22 · answer #8 · answered by Anonymous · 0⤊ 0⤋
formula (a+b)(a-b)=a2-b2
given expression: (31+9)(31-9)
=31sq. - 9sq.
=961-81
=880
Ans;880
2007-06-12 11:37:06 · answer #9 · answered by JMdipto 3 · 0⤊ 0⤋
9(I^2)-81
2007-06-12 10:58:01 · answer #10 · answered by Anonymous · 0⤊ 0⤋