Question

r²= (r-20)²-(r-10)²​

Answer 1

Answer:

$r = - 30 \: or \: 10$

Step-by-step explanation:

${r}^{2} = ( {r}^{2} - 40r + 400) - ( {r}^{2} - 20r + 100)$

Simplifying we get

$( r + 30)(r - 10)$