What is the number of integer solutions to x1+x2+x3+x4=10x_1 + x_2 + x_3 + x_4 = 10x1+x2+x3+x4=10 with xi≥1x_i \geq 1xi≥1?
(10−14−1)\binom{10-1}{4-1}(4−110−1)
(93)\binom{9}{3}(39)
848484
120120120