Simplify (Square root of)20 + (Square root of)80.?
回答 (9)
2008-11-09 3:27 pm
✔ 最佳答案
√20 + √80= √(2^2 x 5) + √(2^4 x 5)
= 2√5 + 2^2√5
= 2√5 + 4√5
= (2 + 4)√5
= 6√5
2008-11-09 3:39 pm
√20 + √80 = √(4)(5) + √(16)(5) = 2√5 + 4√5 = 6√5
2008-11-09 5:16 pm
√(4 x 5) + √(5 x 16)
2√5 + 4√5
6√5
2√5 + 4√5
6√5
2008-11-09 3:38 pm
20 = 4*4 so sqrt(20) = sqrt(4*5) = sqrt(4)*sqrt(5) = 2*sqrt(5)
80 = 16*5 so sqrt(80) = sqrt(16*5) = sqrt(16)*sqrt(5) = 4*sqrt(5)
2*sqrt(5) + 4*sqrt(5) = 6*sqrt(5)
80 = 16*5 so sqrt(80) = sqrt(16*5) = sqrt(16)*sqrt(5) = 4*sqrt(5)
2*sqrt(5) + 4*sqrt(5) = 6*sqrt(5)
參考: Longtime college math teacher
http://www.CharlesAshbacher.net
2008-11-09 3:31 pm
ok
√20+ √80
you can split
√20 into √4X√5
and split
√80 into √16X√5
√4X√5 gives 2√5
and √16X√5 gives 4√5
2√5+ 4√5
= 6√5
what you need to do is split √ into differnt √s and like you want √a square number to give you a round number
√20+ √80
you can split
√20 into √4X√5
and split
√80 into √16X√5
√4X√5 gives 2√5
and √16X√5 gives 4√5
2√5+ 4√5
= 6√5
what you need to do is split √ into differnt √s and like you want √a square number to give you a round number
2008-11-09 3:30 pm
20=2^2 x 5 , 80=2^4 x 5, (2^2 x 5)^1/2 + (2^4 x 5) =
=2(5)^1/2 + 4(5)^1/2 =6(5)^1/2
=2(5)^1/2 + 4(5)^1/2 =6(5)^1/2
2008-11-09 3:29 pm
sqrt 20 + sqrt 80
= sqrt 2*2*5 + sqrt 2*2*2*2*5
= 2 sqrt 5 + 4 sqrt 5
= 6 sq rt 5
= sqrt 2*2*5 + sqrt 2*2*2*2*5
= 2 sqrt 5 + 4 sqrt 5
= 6 sq rt 5
2008-11-09 3:27 pm
sqrt(20) = sqrt(4*5) 2sqrt(5)
sqrt(80) = sqrt(16*5) 4sqrt(5)
Since both square roots have the same radicand, 5, we can add the coefficients.
(2+4)sqrt(5)
6squareroot(5) is the answer.
sqrt(80) = sqrt(16*5) 4sqrt(5)
Since both square roots have the same radicand, 5, we can add the coefficients.
(2+4)sqrt(5)
6squareroot(5) is the answer.
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