Question

Find the pair of integer whose product is -15 and whose difference is 8

Answer 1

Answer:

11,3 or 13,5

Step-by-step explanation:

let the no.s be x and y (x>y)

given xy= -15--[1] and x-y=8--[2]

in equation 2

x-y=8

=>x=y+8--[3]

by substituting equation 3 in equation 1

(y+8)(y)= -15

$y^{2} - 8y$=-15

$y^{2} - 8y$ +15=0

$y^{2} -3y-5y +15$=0

y(y-3)-5(y-3)

(y-3)(y-5)=0

y=3 or 5

case i) when y=3 then x=11

case ii) when y=5 then x=13

therefore the pair of integers are 11,3 or 13,5