There are 9 students ain class 2 boys 7 girls and a teacher picks 4 at random what is the probability in the group that everyone is a girl

2/3.

Step-by-step explanation:

Ok, so at first, the probability of the teacher picking a girl is 7/9. And then when she takes one girl, it is less, so the probability is 6/8. Then if she picks 2 more girls, then the probability of that would be 4/6, or 2/3.

- 2 + 10x³ - 21x² + 19x - 4

step-by-step explanation:

each term in the second factor is multiplied by each term in the first factor

x²(- 2x² + 4x - 1) - 3x(- 2x² + 4x - 1) + 4(- 2x² + 4x - 1) ← distribute

= - 2 + 4x³ - x² + 6x³ - 12x² + 3x -8x² + 16x - 4

collect like terms

= - 2 + 10x³ - 21x² + 19x - 4 ← in standard form