Math, asked by PriyanshuKumar1587, 1 year ago

( x - 1)⅔ =25 please tell me the solution of this question

Answers

Answered by hukam0685
5
Solution:

 {(x - 1)}^{ \frac{2}{3} }  = 25 \\
taking power 3/2 both sides

 {(x - 1)}^{ \frac{2 \times 3}{3 \times 2} }  =  {(25)}^{ \frac{3}{2} }  \\  \\ x - 1 =  {5}^{2 \times  \frac{3}{2} }  \\  \\ x - 1 =  {5}^{3}  \\  \\ x - 1 = 125 \\ x = 125 + 1 \\  \\ x = 126
Hope it helps you.
Answered by Shubhendu8898
8

Given,

(x-1)^{\frac{2}{3}}=25\\\\Using,\;\;a^{n}=b\implies\;a=b^{\frac{1}{n}}\\\\(x-1)=25^{\frac{3}{2}}\\\\x-1=\sqrt{25^{3}}\\\\x-1=\sqrt{25\times25\times25}\\\\x-1=\sqrt{5^{2}\times5^{2}\times5^{2}}\\\\x-1=\sqrt{5^{2+2+2}}\\\\x-1=\sqrt{5^{6}}\\\\x-1=\pm5^{3}\\\\x-1=\pm125\\\\\textbf{Taking +ve}\\\\x-1=125\\\\x=125+1\\\\x=126\\\\\\\textbf{Taking -ve}\\\\x-1=-125\\\\x=-125+1\\\\x=-124

Hence,

x = 126 or  x = -124


hukam0685: if there is x^2 in LHS then only we are taking ± sign when removing underroot
Shubhendu8898: Consider it as x-1 =y, then, y=√5^6; y²= 5^6
hukam0685: in that case too u need not to square both side,since y= √5^6 = √(5^3)^2 = 5^3= 125
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