Đáp án:
`P = -4sqrt(2)`
`R = 28`
`M = 6`
Giải thích các bước giải:
`P = 2/(1-sqrt(2)) - 2/(1+sqrt(2))`
`= (2(1+sqrt(2))-2(1-sqrt(2)))/(1^2-(sqrt(2))^2)`
`= (2+2sqrt(2)-2+2sqrt(2))/(1-2)`
`= (4sqrt(2))/(-1) = -4sqrt(2)`
$$$$
`R = 2/(7+4sqrt(3)) + 2/(7-4sqrt(3))`
`= (2(7-4sqrt(3))+2(7+4sqrt(3)))/(7^2-(4sqrt(3))^2)`
`= (14-8sqrt(3)+14+8sqrt(3))/(49-48)`
`= 28/1=28`
$$$$
`M = (3sqrt(2)-2sqrt(3))/(sqrt(3)-sqrt(2)) : 1/(sqrt(6))`
`= ( sqrt(3) . sqrt(3) . sqrt(2) - sqrt(2) . sqrt(2) . sqrt(3) )/(sqrt(3) - sqrt(2)) . sqrt(6)`
`= ( sqrt(3) . sqrt(2) . ( sqrt(3) - sqrt(2) ))/(sqrt(3)-sqrt(2)) . sqrt(6)`
`= sqrt(3) . sqrt(2) . sqrt(6)`
`= sqrt(6) . sqrt(6) = 6`
