Answer:
x² - r² = (x-r)(x+r)
Step-by-step explanation:
x² - r² = (x-r)(x+r) = x²+xr - xr - r² = x² - r²
or
x² - r²= x² + xr - xr -r²= x(x+r) - r(x+r) = (x+r)(x-r)
