Question

va rog de la a pana la d sunt în timpul testului!! ​Clasa a-7!!

Answer 1

Răspuns:

a.)

$(4\sqrt{2} -2\sqrt{2})x+(6\sqrt{2}-3\sqrt{2})x-(8\sqrt{2}-\sqrt{2})x+3\sqrt{2}x=\\2\sqrt{2}x+3\sqrt{2}x-7\sqrt{2}x+3\sqrt{2}x=\\x(2\sqrt{2}+3\sqrt{2}-7\sqrt{2}+3\sqrt{2})=\\x(5\sqrt{2}-7\sqrt{2}+3\sqrt{2})=\\x(-2\sqrt{2}+3\sqrt{2})= x\sqrt{2}$

b.)

$(5\sqrt{3}-\sqrt{12})a+(\sqrt{27}-7\sqrt{3})a+(2\sqrt{75}-3\sqrt{108}= \\ (5\sqrt{3}-2\sqrt{3})a+(3\sqrt{3}-7\sqrt{3})a+(2*5\sqrt{3}-3*6\sqrt{3})a=\\3\sqrt{3}a+(-4\sqrt{3})a+(10\sqrt{3}-18\sqrt{3})a=\\3\sqrt{3}a-4\sqrt{3}a+(-8\sqrt{3})a=\\a(3\sqrt{3}-4\sqrt{3}-8\sqrt{3})=\\a(-1\sqrt{3}-8\sqrt{3})= \\a(-9\sqrt{3})= -9a\sqrt{3}$

c.)

$(2\sqrt{28}+\sqrt{63})xy-\sqrt{50}xy+(\sqrt{8}+\sqrt{18}) xy+\sqrt{175}xy= \\(2*2\sqrt{7}+3\sqrt{7})xy-5\sqrt{2}xy+(2\sqrt{2}+3\sqrt{2})xy+5\sqrt{7}xy=\\(4\sqrt{7}+3\sqrt{7})xy-5\sqrt{2}xy+5\sqrt{2}xy+5\sqrt{7}xy=\\xy(7\sqrt{7}-5\sqrt{2}+5\sqrt{2}+5\sqrt{7})=\\xy(7\sqrt{7}+0+5\sqrt{7})= 12xy\sqrt{7}$

d.)

$3\sqrt{6}x^{2}+(2*5\sqrt{6}-3\sqrt{6})x^{2} +(8\sqrt{3}-5\sqrt{3})x^{2} +7\sqrt{3}x^{2}-\sqrt{6}x^{2} =\\3\sqrt{6}x^{2} +(10\sqrt{6}-3\sqrt{6})x^{2}+3\sqrt{3}x^{2} +7\sqrt{3}x^{2} -\sqrt{6}x^{2} =\\3\sqrt{6}x^{2} +7\sqrt{6}x^{2} +3\sqrt{3}x^{2} +7\sqrt{3}x^{2} -\sqrt{6}x^{2} =\\x^{2} (3\sqrt{6}-7\sqrt{6}+3\sqrt{3}+7\sqrt{3}-\sqrt{6})=\\x^{2} (-4\sqrt{6}+3\sqrt{3}+7\sqrt{3}-\sqrt{6})=(-5\sqrt{6}+10\sqrt{3})x^{2}$