Question

The square root of $71\ast 72\ast 73\ast 74+1$ is ____

• A. $9375$
• B. $9625$
• C. $5625$
• D. $5255$

Answer 1

The correct option is D $5255$

$71\ast 72\ast 73\ast 74+1$. . . . . . .(1)

let, $x=71$

Equation (1),

$x(x+1)(x+2)(x+3)+1$

$(x^2+3x)(x^2+3x+2)+1$

$(x^2+3x{)}^2+2(x^2+3x)+1$

$(x^2+3x+1{)}^2$

The square root, $\sqrt{(x^2+3x+1{)}^2}$

$=x^2+3x+1$

$=(71{)}^2+3(71)+1$

$5041+213+1=5255$

The correct option is D.