Math, asked by Anonymous, 9 months ago

A man’s age after 15 years will be the square of his age 15 years ago. Find
the age using completing the square method.

Answers

Answered by mansiqueen14357
3

Answer:

hope it helps you..............

Attachments:
Answered by franktheruler
0

Man's present age is 21 years .

Given :

A man's age after 15 years will be the square of his age 15 years ago.

To find out : Man's present age.

Solution : We are given information that a man's age after 15 years will be the square of his age 15 years ago.

Depending on this information , we will have to frame an equation.

Let present age of a man is x years.

After 15 years his age will be ( x + 15) years.

15 years ago his age was ( x - 15 ) years.

According to the given information , the equation will become ,

( x + 15 ) = ( x - 15 )²

here we will be using the formula

( a - b )² = a² - 2ab + b²

a = x, b = 15

therefore by solving

( x - 15 )² = x² - 2 x 15 x X - (15)²

= x² - 30x -225

hence

( x + 15 ) = x² - 30x - 225

putting the x terms together we get

x² - 30x - x = -225 + 15

x² -31 x = - 210

Adding ( 31/2)² both the sides

x² -31 x + 31/2)² = 210 - ( 31/2)²

( x - 31/2 ) ² = 210 - 961/4

( x - 31/2 ) ² = (840 - 961 ) /4

(x - 31/2 ) ² = 121/4

Taking square root both the sides

x - 31/2 = + 11/2 or - 11/2

solving we get

x = 21 or x = 10

x = 10 is not possible so x = 21 is the correct solution.

Hence Man's present age is 21 years .

#SPJ2

Related questions

https://brainly.in/question/8132221

https://brainly.in/all-questions

Similar questions