bài 1 ; thực hiện phép tính
a, \(\left(\sqrt{12}+\sqrt{75}+\sqrt{27}\right):\sqrt{15}\)
b, \(\sqrt{252}-\sqrt{700}+\sqrt{1008}-\sqrt{448}\)
c, \(\sqrt{27^2-23^2}+\sqrt{37^2-35^2}\)
d,\(\left(\sqrt{\dfrac{1}{7}}+\sqrt{\dfrac{16}{7}}+\sqrt{\dfrac{9}{7}}\right):\sqrt{7}\)
bài 2 : rút gọn
a, \(A=\dfrac{2}{x^2-y^2}\times\sqrt{\dfrac{3x^2+6xy+3y^2}{4}}\)
b, \(B=\dfrac{1}{2a-1}\times\sqrt{5a^4\left(1-4a+4a^2\right)}\)