Question #a9fdf

1 Answer
Nov 6, 2016

(2,3)" or " (3,2)

Explanation:

Rearrange x + 5y in terms of x or y and substitute into xy = 6.

x+y=5rArry=5-x

substitute this into xy = 6

rArrx(5-x)=6

distribute and equate to zero.

rArr5x-x^2=6rArrx^2-5x+6=0

Factorising the quadratic gives.

(x-2)(x-3)=0rArrx=2,x=3

x=2toy=5-2=3to(2,3)" is a solution"

x=3toy=5-3=2to(3,2)" is also a solution"

This can be checked fairly ' easily' as follows.

x=2,y=3rArrx+y=2+3=5" and " xy=2xx3=6

x=3,y=2rArrx+y=3+2=5" and " xy=3xx2=6