Question

what adds to get 9 and multplies to get 4

Answer 1

x+y=9
xy=4

x+y=9
subtrac x
y=9-x

subsitute
x(9-x)=4
9x-x^2=4
add to both sides
0=x^2-9x+4
use quadratice formula
if 0=ax^2+bx+c  then
x=$\frac{-b+/- \sqrt{b^{2}-4ac} }{2a}$

x^2-9x+4=0
a=1
b=-9
c=4

x=$\frac{-(-9)+/- \sqrt{(-9)^{2}-4(1)4} }{2(1)}$
x=$\frac{9+/- \sqrt{81-16} }{2}$
x=$\frac{9+/- \sqrt{65} }{2}$
aprox
x=0.468817 or 8.5311

the numbers are interchangable so

the numbers are 0.468817 and 8.5311