Ten times the square of a non-zero number is equal to seventy times the number. What is the number?

The original number is 7 i think.

10 (x^2) = 70x

10x^2 - 70x = 0

x^2 - 7x = 0

Δ = b^2 - 4ac

where c doesnt exist=0

Δ = 49

-b ± √Δ / 2a

7 ± √49 / 2

7±7/2

x is either 14/2 = 7

or 1/2, which doesnt work.

Lets see:

10 (7^2) = 70•7

10•49 = 490

and that is right.

i hope my logic is correct.