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If 4x + 3 = 112 + 8 × 4x, Find the Value of (18x)3x. - Mathematics

Sum

If 4x + 3 = 112 + 8 × 4x, find the value of (18x)3x.

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Solution

4x + 3 = 112 + 8 × 4
⇒ 4x x 43 = 112 + 8 x 4
⇒  64 x 4x = 112 + 8 x 4x 
Let 4x = y
64y = 112 + 8y
⇒ 56y = 112
⇒ y = 2
Substituting We get,
4= 2
⇒ 22x = 2
⇒ 2x = 1
⇒ x = `1/2`

`( 18x )^(3x)  = (18/2)^( 3 xx 1/2 ) = 9^( 3 xx 1/2 ) = ( 9^(1/2))^3 = 3^3 = 27`

Concept: Solving Exponential Equations
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APPEARS IN

Selina Concise Mathematics Class 9 ICSE
Chapter 7 Indices (Exponents)
Exercise 7 (B) | Q 13 | Page 101
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