The product of age of a person 10 year ago and 10 year after is 156.find

The age of the person now is 16 years old

Step-by-step explanation:

Let us solve the question

Assume that the age of the person now is x years old

∵ The age of the person now is x years old

∵ His age 10 years ago = x - 10

∵ His age 10 years after = x + 10

∵ The product of his ages 10 years ago and 10 years after is 156

→ Multiply his ages before and after and equate the product by 156

∴ (x - 10)(x + 10) = 156

∵ (x - 10)(x + 10) = (x)(x) + (x)(10) + (-10)(x) + (-10)(10)

∴ (x - 10)(x + 10) = x² + 10x - 10x - 100

→ Add the like terms

∴ (x - 10)(x + 10) = x² + (10x - 10x) - 100

∴ (x - 10)(x + 10) = x² - 100

→ Substitute it in the equation above

∵ x² - 100 = 156

→ Add 100 to both sides

∴ x² - 100 + 100 = 156 + 100

∴ x² = 256

→ Take √  for both sides

∴ √x² = √256

∴ x = 16

∵ x represents his age now

∴ The age of the person now is 16 years old

is means division by fractions

step-by-step explanation: