Question

Calculati: (2x-y)²;(4+2x)²; (2√2-3a)(2√2+3a);

Answer 1

$(2x-y)^2 = 4x^2 - 2*2x*y +y^2= 4x^2 - 4xy+ y^2$
$(4+2x)^2 = 16+2*2x*4+4x^2 = 16+16x+4x^2$
$(2 \sqrt{2} -3a)(2 \sqrt{2} +3a) = 4*2 - 9a^2 = 8-9a^2$
Formulele de calcul prescurtat

Answer 2

$(2x-y)^2=(2x)^2-2 \cdot 2x \cdot y+y^2=4x^2-4xy+y^2 \\ (4+2x)^2=4^2+2 \cdot 4 \cdot 2x+(2x)^2=16+16x+4x^2 \\ (2 \sqrt{2} -3a)(2 \sqrt{2} +3a)=8-9a^2$