Question

va rog am test , îmi trebe un 7 minim va rog
​

Answer 1

g)A²4=4!/(4-2)!=1×2×3×4/2=12

h)A²9=9!/(9-2)!=9!/7!=7!×8×9/7!=72

i)C³7=7!/(7-3)!×3!=7!/4!×3!=4!5×6×7/4!×3!=

5×6×7/2×3=5×7=35

j)C³11=11!/(11-3)!3!=11!/9!3!=9!10×11/9!3!=

110/2×3=55/3

k)C²9-C⁷9=9!/(9-7)!2!-9!/(9-7)!7!=

9!/2!2!-9!/2!7!=9!/2(1/2-1/7!)=

9!/2(7!-2)/2×7!=72×(7!-2)/4=18(7!-2)