... M (1 13 ) 3 Cõu 7b Tacú: 12 12 (1+ x+x ) =[ (1+ x)+x ] = (1. 0 k 12 im) =C12 (1 + x )12 + C12 (1 + x )11 x + + C12 (1 + x )12 - k ( x )k + +C12 x 24 0 C12 [C12 x12 + C12 x 11 + + C12 x + ]+C12 x [C 11 ... x 11 + + C12 x + ]+C12 x [C 11 x 11 + + C11x + ] = 10 +C12 x [C10 x10 + +C10 ]+ 0,25 0,25 0,25 0,25 ị Chcú3shnguchax 10 ị a4 = C12 C12 + C12 C 11 + C12 C10 =12 21 0,25 0,25 ... + 1 +Ơ + +Ơ 0,25 1 -Ơ Hsngbintrờnkhong( -Ơ 1) v (1 +Ơ ),nghchbin trờn ( 11 ) Hstccitix=ư1vyc=3,Hstcctiutix=1vyct= 1 th:ctOytiimA( 01) viquacỏcimB(ư2 1) ,C(23) thnhnimA( 01) lmtõmixng 0,25 y ư2 ư1...