Question

Докажите тождество (2-0.9х)(0.9х+2)-10+0.81х^2=-6

Answer 1

(2-0,9х)(2+0,9х) - 10 + 0,81х^2 = 4 - 0,81x^2 - 10 + 0,81x^2 = 4 - 10 = -6