1,thu gon bieu thuc
a A=\(\dfrac{a\sqrt{a}-8+2a-4\sqrt{a}}{a-4}\)
b,B=\(\dfrac{12\sqrt{6}}{\sqrt{7+2\sqrt{6}-\sqrt{7-2\sqrt{6}}}}\)
c, C=\(\dfrac{\sqrt{c^2+2c+1}}{\left|c\right|-1}\)
2,giai cac phuong trinh
a,\(x^2-9\sqrt{x}+14=0\)
b, \(\sqrt{3x^2-18x+28}+\sqrt{4x^2-24x+45}=-5-x^2+6\)
GIUP MINH VOI MINH CAN GAP