(x-4)²+2(4+x)(4-x)+(x+4)² подскажите !

(x-4)^2 + 2 • (4+x) • (4-x) + (x+4)^2 = (4+x)^2 + 2 • (16-x) + (4+x)^2 = 2 • (4+x)^2 + 2 • (16-x^2) = 2 • (4+x + 16-x^2) = 2 • (x • (4 - 16x)) = 2x • 4 • (1 - 4x) = 8x • (1 - 4x)