can anyone solve this quadratic equation using completing the square method?
(5x-4)^2 = 24
full worked solutions please..
thanks!! ;D
help me with my maths homework!?
2008-12-26 8:32 am
回答 (7)
2008-12-26 8:44 am
✔ 最佳答案
Given: (5x-4)^2 = 24expand (5x-4)^2=
25x^2 - 40x + 16
so
(5x-4)^2 = 24
25x^2 - 40x + 16 = 24
25x^2 - 40x = 24 -16
25x^2 - 40x = 8 (divide both side by 25)
x^2 - 8x/5 =8/25
Now complete the square.
(x^2 - 8x/5 + __) =8/25 + __
(x^2 - 8x/5 + 16/25) = 8/25 + 16/25
(x-4/5)^2 = 24/25
(x-4/5) = √(24/25)
x-4/5=+ or -(2√6)/5
x=4/5 + or -(2√6)/5
x=(4+2√6)/5 (answer)
or
x=(4-2√6)/5 (answer)
2008-12-26 4:53 pm
5x - 4 = 屉24
5x - 4 = ± 2â6
5x = 4 ± 2â6
x = (4 ± 2â6) / 5
x = (2/5) (2 ± â6)
5x - 4 = ± 2â6
5x = 4 ± 2â6
x = (4 ± 2â6) / 5
x = (2/5) (2 ± â6)
2008-12-26 5:40 pm
(5x - 4)² = 24
5x - 4 = 4.8989794
5x = 8.8989794
x = 1.7797958
Answer: x = 1.7797958
5x - 4 = 4.8989794
5x = 8.8989794
x = 1.7797958
Answer: x = 1.7797958
2008-12-26 10:52 pm
(5x - 4)^2 = 24
5x - 4 = 屉24
5x - 4 = 屉(2^2 * 6)
5x = 4 ±2â6
x = (4 ±2â6)/5
5x - 4 = 屉24
5x - 4 = 屉(2^2 * 6)
5x = 4 ±2â6
x = (4 ±2â6)/5
2008-12-26 4:42 pm
25x^2-40x +16 = 24
25x^2-40x-8=0
a=25, b=-40, c=-8
x= (-b +/- (b^2-4ac)^1/2 )/2a
25x^2-40x-8=0
a=25, b=-40, c=-8
x= (-b +/- (b^2-4ac)^1/2 )/2a
2008-12-26 4:37 pm
25 x^2 + 16 - 40x = 24
25 x^2 -8 +40x=0
solve using discriminant, you'd get the answer!
25 x^2 -8 +40x=0
solve using discriminant, you'd get the answer!
2008-12-26 4:46 pm
(5x-4)^2 = 24
25x-16 = 24
25x ( +16 ) = 24 ( +16 )
25x = 40
x = 40/25 ( 1 3/5 )
25x-16 = 24
25x ( +16 ) = 24 ( +16 )
25x = 40
x = 40/25 ( 1 3/5 )
收錄日期: 2021-05-01 11:41:15
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