(√?-1)²=8-√28 Find Underoot
Answers
Answer:
let x be the number under root
then (√x - 1)^2 = 8 - √28
=> x + 1 - 2√x = 8 - √28
=> x - 2√x = 8 - √28 - 1
=> x - 2√x = 7 - √28
=> x - 2√x = 7 - 2√7 [ √28 = √ 4×√7 = 2√7 ]
=> on comparing LHS and RHS,
we get x = 7
therefore under root is 7 Answer
Answer:
The value of x is 7
Step-by-step explanation:
Given:
(√x-1)² = 8- √28
To find the value of x
Solution:
Let, left hand side = L.H.S.
Let, right hand side = R.H.S.
Consider the L.H.S.,
We know that, (a²- b²= a² + b² - 2ab)
Now, by applying the above formula,
=>(√x)² + (1) - 2x (1) × (√x)
=>x+1 - 2× √x = 8 - √28
Consider the R.H.S.,
=> 8-√28 = 8 - (√7×4)
=> 8-√28 = 8 - (√7 ×(2)²)
Since,√2)² = 2, we get
=>8 -√28 = 8-2× (√7)
Hence, x+1 - 2 × √x = 8-2 × √(7)
=> x-2 × √x = 7 -2 × √(7)
=>√x(√x-2 ) = √7 (√7-2 )
Therefore, by considering the L.H.S and R.H.S,
it is understood that x=7
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