√(2x-6) + √(x+4) =5. Pls solve this question with detailed steps!!
Answers
Answered by
24
Square both sides:
(2x - 6) + (x + 4) + 2 sqrt ((2x - 6)(x + 4)) = 25
Then isolate the remaining sqrt term:
2 sqrt ((2x - 6)(x + 4) = 27 - 3x
Then square both sides:
4 (2x - 6)(x + 4) = 729 - 162x + 9x²
Expand:
8x² + 8x - 96 = 729 - 162x + 9x²
Put all on one side:
x² - 170x + 825 = 0
Solve by quadratic formula or otherwise:
x = (170 +/- sqrt (170² - 3300)) / 2
= (170 +/- 160) / 2
= 5 or 165.
But for some reason 165 doesn't work, so x = 5.
..
....
......
hope it helps...
plZz Mark as a brainliest!!
(2x - 6) + (x + 4) + 2 sqrt ((2x - 6)(x + 4)) = 25
Then isolate the remaining sqrt term:
2 sqrt ((2x - 6)(x + 4) = 27 - 3x
Then square both sides:
4 (2x - 6)(x + 4) = 729 - 162x + 9x²
Expand:
8x² + 8x - 96 = 729 - 162x + 9x²
Put all on one side:
x² - 170x + 825 = 0
Solve by quadratic formula or otherwise:
x = (170 +/- sqrt (170² - 3300)) / 2
= (170 +/- 160) / 2
= 5 or 165.
But for some reason 165 doesn't work, so x = 5.
..
....
......
hope it helps...
plZz Mark as a brainliest!!
abhi178:
cool answer
Answered by
11
√(2x - 6) + √( x + 4) = 5
√{2( x +4) -14} + √(x +4) = 5
let ( x +4) = Q
√{2Q -14) + √Q = 5
√(2Q -14) = 5 - √Q
take square both sides
2Q - 14 = 25 + Q -10√Q
Q -39 = -10√Q
Q + 10√Q -39 = 0
√Q = t
t² + 10t -39 = 0
t² +13t -3t -39 = 0
( t + 13)( t -3) = 0
t = -13 , 3
but t > 0 becoz t = √Q
so,
t = √Q = 3
Q = 9
x + 4 = 9
x = 5
√{2( x +4) -14} + √(x +4) = 5
let ( x +4) = Q
√{2Q -14) + √Q = 5
√(2Q -14) = 5 - √Q
take square both sides
2Q - 14 = 25 + Q -10√Q
Q -39 = -10√Q
Q + 10√Q -39 = 0
√Q = t
t² + 10t -39 = 0
t² +13t -3t -39 = 0
( t + 13)( t -3) = 0
t = -13 , 3
but t > 0 becoz t = √Q
so,
t = √Q = 3
Q = 9
x + 4 = 9
x = 5
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