Question

one year ago a man was 8 times as old as his son. now his age is equal to the square of his son?s age. find their present ages. quadratic equation

Answer 1

One years ago,
Man's age = x - 1
Son' s age = y - 1
A/q
x - 1 = 8 ( y - 1 )
x - 8y = -7 ...............(i)
Present age of
Man = x
Son = y
Given:
x = yy ........................(ii)
put the value of x = yy in eq. (i)
x - 8y = -7
yy - 8y = -7
yy - 8y + 7 = 0
yy -7y - y + 7 = 0
y ( y - 7 ) - 1 ( y - 7 ) = 0
( y - 1 ) ( y - 7 ) = 0
y = 7. ( By crossing y = 1 )
Put the value of y = 7 in eq. (ii)
x = yy
x = 7 x 7
x = 49
Hence the present age of Man is 49 years
And, his son's present age is 7 years