(3-2 √7)(3+2 √7)
2007-08-30 11:12:04 · 9 answers · asked by Anonymous in Science & Mathematics ➔ Mathematics
Hi,
To answer this question, remember this rule
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(a+b) * (a-b) = a² - b²
a² - b² = (a+b) * (a-b)
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Therefore,
(3-2 √7)(3+2 √7)
= 3² - (2√7)²
= 9 - 28
= -19
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Answer: -19
======================
Hope this helps
Kind regard,
Ryonn
2007-08-30 11:14:47 · answer #1 · answered by Mr. Math Contributor 4 · 1⤊ 0⤋
(x-y)(x+y) = x^2 - y^2
(3-2 â7)(3+2 â7) =
3^2 - (2â7)^2 =
9 - (4* 7) =
9 - 28 =
- 19
2007-08-30 11:22:29 · answer #2 · answered by petep73 3 · 0⤊ 0⤋
9 + 6â7 - 6 â7 - 28
- 19
2007-09-03 10:53:30 · answer #3 · answered by Como 7 · 0⤊ 0⤋
(3 - 2â7)(3 + 2â7) =
(1â7) (5â7) =
(â7)(5â7) =
5 â49 =
5 x 7 =
35
- - - - - - - s-
2007-08-30 11:33:36 · answer #4 · answered by SAMUEL D 7 · 0⤊ 2⤋
Mr. Math Contributor is right. It's what's known as the "difference of two squares".
(a + b) (a - b) = (a squared) + (b squared)
In this case, a = 3 and b = 2 * (sqrt 7)
2007-08-30 11:21:21 · answer #5 · answered by jackalanhyde 6 · 0⤊ 0⤋
(3-2v7) (3+2v7)
Use FOIL method
9 + 6v7 + -6v7 + -4*7
add like terms
9 + -28
so the answer is
-19
(I do not have a sq root sign so I used v)
2007-08-30 11:24:27 · answer #6 · answered by gracie 2 · 0⤊ 0⤋
FOIL
F
9
O
6sqrt7
I
-6sqrt7
L
-2*2*sqrt7*sqrt7
-4*7
-28
Total
9 -28
19
2007-08-30 11:18:13 · answer #7 · answered by I have 0 characters to work with 3 · 0⤊ 3⤋
the answer is 35, it wouldnt get more simple then that.
2007-08-30 11:16:09 · answer #8 · answered by thegoatstheglory 2 · 0⤊ 5⤋
3.2/7
2007-08-30 11:15:43 · answer #9 · answered by Anonymous · 0⤊ 5⤋