Question

21x^2-20x=0

my answers are 0, 20/21
is this correct?

Answer 1

21 x^2 - 20x =0

factor out x
x (21 x -20) =0

this means either x=0 or 21 x -20 =0
the 2nd equation is
21 x -20=0
add 20 to both sides
21 x = 20
divide both sides by 21
x= 20/21

Answer 2

you could replace x with your answers to check if they are correct.
x=0 is easy to check:
21*0*0 - 20*0 is 0 -0 or just 0

Answer 3

so my answers are correct. :) awesome! finally getting a hang of this.

Answer 4

thank you for your help! it was very appreciated!