Question

thực hiện phép tính (rút gọn)

a, \(\sqrt{4\left(a-5\right)^2}\)với a lớn hơn hoặc bằng 5

b, \(\sqrt{4-2\sqrt{3}}\)-\(\sqrt{3}\)

c, \(\sqrt{8+2\sqrt{5}}\)-\(\sqrt{5}\)

d, \(\sqrt{\left(3-2\sqrt{3}\right)}^2\)-\(\sqrt{\left(3+2\sqrt{2}\right)}^2\)

e, \(\sqrt{24\left(b-3\right)}^2\)với b ^{nhỏ hơn 3}

Answer 1

a,\(\sqrt{4\left(a-5\right)^2}=\sqrt{4}.\sqrt{\left(a-5\right)^2}=2.\left|a-5\right|=2\left(a-5\right)\left(a\ge5\right)\)

b,\(\sqrt{4-2\sqrt{3}}-\sqrt{3}=\sqrt{\left(\sqrt{3}-1\right)^2}-\sqrt{3}=\sqrt{3}-1-\sqrt{3=-1}\)

c,Mạn phép sửa đề ,nếu ko thì kết quả ko đẹp

\(\sqrt{8+2\sqrt{15}}-\sqrt{5}=\sqrt{\left(\sqrt{5}+\sqrt{3}\right)^2}-\sqrt{5}=\sqrt{5}+\sqrt{3}-\sqrt{5}=\sqrt{3}\)

d,\(\sqrt{\left(3-2\sqrt{3}\right)^2}-\sqrt{\left(3+2\sqrt{3}\right)^2}=2\sqrt{3}-3-3-2\sqrt{3}=-6\)

e,\(\sqrt{24\left(b-3\right)}^2=\sqrt{24^2}.\sqrt{\left(b-3\right)^2}=24.\left(3-b\right)\left(b< 3\right)\)