the sum of the ages of a boy and his elder brother is 12 years and the sum of the square of their in 74 in years .find their ages
Answers
Answered by
1
boy age is 5 year and his elder brother's age is 7 year.
Answered by
2
let the age of boy be (12-x)yrs
let the age of elder brotherbe x yrs
according to question
x^2+(12-x)^2=74
x^2+144+x^2-24x=74
2x^2+144-74-24x=0
2x^2-24x+70=0
2(x^2-12x+35)=0
x^2-12x+35=0
x^2-(7+5)x+35=0
x^2-7x-5x+35=0
x(x-7)+5(x-7)=0
(x-7)+(x+5)=0
either x=7 or x=-5(which is not possible)
Therefore age of boy is 5years and his elder brother age is 7years.
let the age of elder brotherbe x yrs
according to question
x^2+(12-x)^2=74
x^2+144+x^2-24x=74
2x^2+144-74-24x=0
2x^2-24x+70=0
2(x^2-12x+35)=0
x^2-12x+35=0
x^2-(7+5)x+35=0
x^2-7x-5x+35=0
x(x-7)+5(x-7)=0
(x-7)+(x+5)=0
either x=7 or x=-5(which is not possible)
Therefore age of boy is 5years and his elder brother age is 7years.
Similar questions