Question

Five years hence the age of jacob will be three times that of his son.five years ago Jacobs age as seven times that of his son let x be jacob age y his son's age.

Answer 1

Explanation:

let Jacob's and his son's age be x and y respectively.

5 yrs hence:

Jacob'sage=x+5

son's age =y+5

so according to 1 condition:

x+5=3(y+5)

x+5=3y+15=0

x-3y+5-15=0

x-3y-10=0

5 yrs ago :

Jacob's age =x-5

son's age =y-5

so according to 2condition:

x-5=7(y-5)

x-5=7y-35

x-7y -5+35=0

x-7y+30=0

on substracting eq 1 from 2

x-7y+30-(x-3y-10)=0

x-7y+30-x+3y+10=0

-4y +40 =0

-4y=-40

4y=40

y=10

now putting y =10 in any of the two equations we can find the value of x.

suppose putting y=10 in eq 1

x-3y-10=0

x-3×10-10=0

x-30-10=0

x-40=0

x=40

therefore Jacob's age is 40 yrs and his son's age is 10 yrs..

Answer 2

Answer:

Please refer the attachment dear