Question

Half of the sum of two numbers is 12, while one-fourth of their products is 35. Find the numbers

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Answer 1

10 and 14

Explanation:

let the 2 numbers be x and y , then

`(1)/(2)` (x + y) = 12 ( multiply both sides by 2 to clear the fraction )

x + y = 24 ( subtract x from both sides )

y = 24 - x → (1)

and

`(1)/(4)` xy = 35 ( multiply both sides by 4 )

xy = 140 → (2)

substitute y = 24 - x into (2)

x(24 - x) = 140

24x - x² = 140 ( subtract 140 from both sides )

24x - x² - 140 = 0 ( multiply through by - 1 and arrange in standard form )

x² - 24x + 140 = 0 ← in standard form

(x - 10)(x - 14) = 0 ← in factored form

equate each factor to zero and solve for x

x - 10 = 0 ⇒ x = 10

x - 14 = 0 ⇒ x = 14

corresponding values of y are by substituting values of x into (1)

x = 10 → y = 24 - 10 = 14

x = 14 → y = 24 - 14 = 10

then the numbers are 10 and 14