Question

iska b do jldi se answer guyz

If (x²+3x+5)(x²-3x+5)=m²-n² then m=?
2 points
x²+5
x²-3x
3x
None of these​

Answer 1

LHS

$\mapsto \rm \: ( {x}^{2} + 3x + 5)( {x}^{2} - 3x + 5)$

$\mapsto \rm \: \{( {x}^{2} + 5) + 3x \} \{( {x}^{2} + 5) - 3x \}$

Using :

${ \sf {\boxed{ ({a} + b)(a - b) = {a}^{2} - {b}^{2} }}}$

in this case ,

• a = (x² + 5)
• b = 3x

$\mapsto \rm \: {(x}^{2} + 5) - {(3x)}^{2}$

Now ,

LHS = RHS

$\mapsto \rm \: {(x}^{2} + 5) - {(3x)}^{2} = {m}^{2} - {n}^{2}$

So ,

$\boxed{ \sf{m = {x}^{2} + 5}}$

$\rm \: option \: \bold{a}$