Question

If present age of sankalp is 11 more than 5 times of square of his age before 5 years, then find sankalp's present age.​

Answer 1

Answer:

let the present age of sankalp be x years

5 years ago,

sankalp's age=(x-5)years

By condition:

Sankalp's present age=11+5(x-5)^2

=16(x-5)^2

by using (a-b)^2=a^2+b^2-2ab formula,we get

=16[(x^2+5^2-2(x)(5)]

=16(x^2+25-10x)

multiplying each term with 16 inside the bracket,we get

=16x^2+400-160x (÷16)

=x^2+25-10x

arrange it correctly for factorisation

x^2-10x+25=0

x^2-5x-5x+25=0

x(x-5)-5(x-5)=0

(x-5)(x-5)=0

x-5=0

x=5

therefore,present age of sankalp is 5 yeras