Question

(a√2+b)•(√2+2)= -2, aflați valoarea numărului b

Answer 1

$(a \sqrt{2} +b)( \sqrt{2} +2)=-2 \\ 2a+2a \sqrt{2} + b\sqrt{2} +2b=-2 \\ 2a \sqrt{2} + b\sqrt{2}=-2-2a-2b \\ \sqrt{2} (2a+b)=-2-2a-2b \\ Daca ~2a+b \neq 0 =\ \textgreater \ \frac{-2-2a-2b }{2a+b} ~apartine~lui~Q~(!!!!FALS!!!!) \\ =\ \textgreater \ -2-2a-2b=0~si~2a+b=0 \\ a=1 \\ b=-2$