Question

solution for 25a^4-40a^2+16

Answer 1

the gn poly is
${25a}^{4} - {40a}^{2} + 16$
Let the Poly be zero

ie

${ ({5a}^{2} })^{2} - 2( {5a}^{2})(4) + {4}^{2} = 0$
ie

$({ {5a}^{2} - 4 })^{2} = 0$
ie

$a = \frac{2}{ \sqrt{5} } (or) \: a = \frac{ - 2}{ \sqrt{5} }$
ie

$a = \frac{2 \sqrt{5} }{5} (or) \: a = \frac{ - 2 \sqrt{5} }{5}$



Since roots are coincident these will repeat

Answer 2

25a^4-40a^2+16

25a^4 - 20a^2 -20a^2 -16

(5a^2 - 4)(5a^2 - 4)

(5a^2 - 4 )^2 = 0

a^ 2 = 4/5

a = +-(4/5)^1/2