【求助】急！两道数学题！！！

EllenChang

1. In the xy-plane, what is the y-intercept of line l ?
(1) the slope of line l is 3 times its y-intercept
(2) the x-intercept of line l is -1/3



2. Of the 12 temporary employees in a certain company, 4 will be hired as permanent employees. if 5 of 12 temporary employees are women, how many of the possible groups of 4 temporary employees consist of 3 women and 1men?

答案是70， 关于4 will be hired as permanent employees这句话在题中有何作用我不是很理解。

谢谢大家！！

calovedebbie

1.问线l 与 y轴的截距？
一次函数中 y=kx+b   b 是y的截距 k 是斜率
也就是问 b 能不能确定

条件1 k=3b
条件2 x=-b/k=-1/3

条件1 俩未知数1个方程无法求出来
条件2 俩未知数1个方程无法求出来

条件1+条件2

发现是等比方程 无法求出来

所以应该是E

calovedebbie

2. C(3,5)*C（1,7）=10*7=70

那个就是说 挑出来4个 作为永久雇佣的 不用在意