How to factor 9s^2-121?
回答 (5)
2008-08-13 4:35 pm
✔ 最佳答案
well since 9 is a square number it becomes 3, and s^2 is a square number and becomes s, while 121 is a square number and its square root is 11so the answer is (3s-11)(3s+11)
2008-08-13 5:10 pm
(3s+11)(3s-11)
2008-08-13 4:44 pm
a^2 - b^2 = (a + b)(a - b)
9s^2 - 121
= 9s^2 + 33s - 33s - 121
= (9s^2 + 33s) - (33s + 121)
= 3s(3s + 11) - 11(3s + 11)
= (3s + 11)(3s - 11)
9s^2 - 121
= 9s^2 + 33s - 33s - 121
= (9s^2 + 33s) - (33s + 121)
= 3s(3s + 11) - 11(3s + 11)
= (3s + 11)(3s - 11)
2008-08-13 4:35 pm
This is a difference of square:
In general: a^2 - b^2 = (a + b)(a - b)
For 9s^2 - 121, we can let a^2 = 9s^2 and 121 = b^2, hence
a = 3s, b = 11
9s^2 - 121 = (3s + 11)(3s - 11)
In general: a^2 - b^2 = (a + b)(a - b)
For 9s^2 - 121, we can let a^2 = 9s^2 and 121 = b^2, hence
a = 3s, b = 11
9s^2 - 121 = (3s + 11)(3s - 11)
2008-08-13 4:34 pm
9s^2-121 = (3s)^2-(11)^2
a^2-b^2=(a+b)(a-b)
(3s+11)(3s-11)
a^2-b^2=(a+b)(a-b)
(3s+11)(3s-11)
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