Question

A boy is five time as old as his sister. Two years ago the sum of the square of their ages was 170. Find the present age of his sister?​

Answer 1

Answer:

yeah

Step-by-step explanation:

let's

sis=x-2

boy=5x-2

now,

(x-2+5x-2)²=170

(6x-4)²=170

36x²-48x+16=170

36x²-48x+16-170=0

36x²-48x-154=0

(let's compare with ax²+bx+c)

where a=36

b=-48

c=-154

then use formula

x=±b√b²-4ac/2a

(then find x value )

then age of sis will be x value .then find sis value )