Toán $\dfrac{√15 – √12}{√a + 2}$ – $\dfrac{1}{2 – √3}$ giúp với 13/07/2021 By Margaret $\dfrac{√15 – √12}{√a + 2}$ – $\dfrac{1}{2 – √3}$ giúp với
` (\sqrt15 -\sqrt12)/(\sqrta +2) – 1/(2-\sqrt3)` `= ((\sqrt15-\sqrt12)(2-\sqrt3) – (\sqrta +2))/((\sqrta+2)(2-\sqrt3)` `= (2\sqrt15 -3\sqrt5-4\sqrt2+4-\sqrta)/(2\sqrta-\sqrt(3a)+4-2\sqrt3)` Trả lời
` (\sqrt15 -\sqrt12)/(\sqrta +2) – 1/(2-\sqrt3)`
`= ((\sqrt15-\sqrt12)(2-\sqrt3) – (\sqrta +2))/((\sqrta+2)(2-\sqrt3)`
`= (2\sqrt15 -3\sqrt5-4\sqrt2+4-\sqrta)/(2\sqrta-\sqrt(3a)+4-2\sqrt3)`