Toán Lớp 9: √15-6√6 √14-6√5 √17-12√2 √27-12√5 √4+√15

Question

Toán Lớp 9:  √15-6√6  √14-6√5  √17-12√2  √27-12√5  √4+√15

behocgioitoan · Answer

Đáp án:       Giải thích các bước giải:

hothaibinh · Answer

&radic;15-6&radic;6     = $ sqrt[]{9-2.3&radic;6 + 6}$      = $ sqrt[]{(3 - &radic;6)&sup2;}$      = 3 - &radic;6     &radic;14-6&radic;5     = $ sqrt[]{(3 - &radic;5)&sup2;}$      = 3 - &radic;5      &radic;17-12&radic;2     = 3&sup2; - 2.3.2&radic;2 + (2&radic;2)&sup2;     = ( 3 - 2&radic;2 )&sup2;     &radic;27-12&radic;5     = $ sqrt[]{3.(9-4&radic;5)}$      = $ sqrt[]{3.(&radic;5 - 2)&sup2;}$  = (&radic;5 - 2) . &radic;3  = &radic;15 - 2 &radic;3     &radic;4+&radic;15     = $ sqrt[]{8+ frac{2&radic;15}{2}}$   = $ sqrt[]{ frac{(&radic;5 + &radic;3)&sup2;}{2}}$ = $ sqrt[]{ frac{2.(&radic;5 + &radic;3)&sup2;}{4}}$ = $ frac{&radic;10 + &radic;6}{2}$