(9х-3) (9х+3) - 8 х² - 39 при х=80

Question

(9х-3) (9х+3) - 8 х² - 39 при х=80

Answer 1

81x^2 - 9 - 8x^2 - 39 = 73x^2 - 48 = 73 * 80^2 - 48 = 73 * 6400 - 48 =  467200 - 48 = 467152

Answer 2

(9x-3) (9x+3)-8 x^2-39 при х=80
81х^2-9-8х^2-39=73х^2-48
73*80^2-48=467152