Question

URGENT ,CELE 2 EX VRGGdau coroana si 100p​

Answer 1

Explicație pas cu pas:

29.

a)

E(x) = (3x+2)² - (2-3x)² + (x-4)(2x-1) - 2(x+6)² + 10(x+7) = (9x²+12x+4) - (9x²-12x+4) +(2x²-x-8x+4) -2(x²+12x+36) + (10x+70) = 9x²+12x+4 - 9x²+12x-4 + 2x²-9x+4 - 2x²-24x-72 + 10x+70 = (11x²-11x²) + (34x-33x) + (78-76) = x + 2

b)

E(1) + E(2) + E(3) + ... + E(25) = (1+2) + (2+2) + (3+2) + ... + (25+2) = (1+2+3+...+25) + 2×25 = ½×25×26 + 50 = 325 + 50 = 375