Đáp án+Giải thích các bước giải:
`b)B=1/3\sqrt{9+6v+v^2} -\frac{4v}{3}+5(v<=-3)`
`=1/3\sqrt{(3+v)^2}-\frac{4v}{3}+5`
`=1/3 |3+v|-\frac{4v}{3}+5`
`=(-v-3)/3-\frac{4v}{3}+5`
`=\frac{-v-3-4v}{3}+5`
`=\frac{-5v-3}{3}+5`
`=\frac{-5v-3+15}{3}`
`=\frac{-5v+12}{3}`
`d)N=t/2 +3/2\sqrt{4-4t+t^2}-2(t<=2)`
`=t/2 +3/2 \sqrt{(2-t)^2}-2`
`=t/2+\frac{3(2-t)}{2}-2`
`=\frac{t+6-3t-4}{2}`
`=\frac{-2t+2}{2}`
`=-t+1`
`f)A=4\sqrt{\frac{25x}{4}}-8/3\sqrt{\frac{9x}{4}}-4/(3x)\sqrt{\frac{9x^3}{64}}(x>0)`
`=\frac{4.5\sqrt{x}}{2}-\frac{8.3\sqrt{x}}{3.2}-\frac{4.3x\sqrt{x}}{3x.8}`
`=10\sqrt{x}-4\sqrt{x}-\frac{\sqrt{x}}{2}`
`=6\sqrt{x}-\frac{\sqrt{x}}{2}`
`=\frac{12\sqrt{x}-\sqrt{x}}{2}`
`=\frac{11\sqrt{x}}{2}`
