Question

what are the solutions of the quadratic equation?
X^2-9x+20=0

Answer 1

(x-5)(x-4) = 0
-5 x - 4 = 20
and
-5x - 4x = -9
^_^

Answer 2

20 can be written as 4*5
now if we write the equation as
X^2-4X-5X+20=0
(X-5)(X-4)=0
x=5,4

Answer 3

x^2 -4x -5x +20 =0
x(x-4) -5 (x -4)=0
(x-5)(x-4)=0
either
x-5=0 or x-4=0
x=5 or x=4
if you want to check the answer either it is correct or wrong
put the value which you get in the given equation
for instance
x=5
since, x^2 -9x +20=0
5^2 -9(5)+20=0
25 -45 +20 =0
45-45=0
0=0
hence proved like this you can check the answer......