The sum of 2 positive numbers is 151. The lesser number is 19 more than the square root of the greater number. What is the greater number?

Respuesta :

The greater number is 121

Step-by-step explanation:

The given is:

  • The sum of 2 positive numbers is 151
  • The lesser number is 19 more than the square root of the greater number

We need to find the greater number

Assume that the smaller number x and the greater number is y

∵ The smaller number is x and the greater number is y

∵ Their sum is 151

x + y = 151 ⇒ (1)

∵ The lesser number is 19 more than the square root of the greater

   number

x = 19 + √y ⇒ (2)

- Substitute x in equation (1) by equation (2)

∵ (19 + √y) + y = 151

- Subtract 151 from both sides and re-arrange the terms from

  the greatest power y

y + √y - 132 = 0

Chang [tex]\sqrt{y}[/tex] to [tex]y^{\frac{1}{2}}[/tex] and substitute  [tex]y^{\frac{1}{2}}[/tex] by h

∵ [tex]y^{\frac{1}{2}}[/tex] = h

∴ y = h²

- Substitute each y by h

∴ h² + h - 132 = 0

- Factorize it into two factors

∴ (h - 11) (h + 12) = 0

- Equate each factor by 0 to find h

∵ h - 11 = 0

- Add 11 to both sides

∴ h = 11

∵ h + 12 = 0

- subtract 12 from both sides

∴ h = -12

∵ h = [tex]y^{\frac{1}{2}}[/tex]

∴ [tex]y^{\frac{1}{2}}[/tex] = 11 and -12

∵ [tex]y^{\frac{1}{2}}[/tex] = √y

∴ √y = 11

∴ √y = -12 ⇒ rejected square root can't give -ve number

√y = 11 only

- To find y square the both sides

y = 121

The greater number is 121

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You can learn more about the word problem in brainly.com/question/4034547

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