Question

Va rog frumos ajutatima la exercitiile 1 si 2 primele doua randuri folosind formulele : {a-b}{a+b}=a²-b² si  asta :  {a+b+c}=a²+b²+c²+2ab+2ac+2bc     sper sa ma puteti ajuta

Answer 1

(x+2)(x-2) = x²-2²
(3x+5)(3x-5) = (3x)²- 5² = 9x² - 25

(a+x+2)² = a² + x² + 2² + 2ax +2×2a + 2×2x = a²+x²+4+2ax +4a +4x 

Answer 2

(1)a)(x+2)(x-2)=x²-4.....b)(x+15)(x-15)=x²-225....c)(3x+5)(3x-5)=9x²-25....d)(2x+y)(2x-y)=4x²-y²...{2}a)(a+x+2)²=a²+x²+4+ax+2a+2x....b)(x+9y+1)²=x²+81y²+1+9xy+x+9y......c)(3x+2y+4)²=9x²+4y²+16+6xy+12x+8y....d)(5a+7b+3c)²=25a²+49b²+9c²+35ab+15ac+21bc........e)(2x²-y-3)²=4x⁴+y²+9-2xy²-6x²+3y