Zeros is the root of the equation, x=-7 or 6,

Bigger than ...

2) 420 is the answer, 420 = 20 2+4 2+2 2.

3) Answer

B sales exceed costs by 25%.

Cost *( 1+25%)=80 and cost =64.

100*(60-45)+50*(80-64)=2300

4) Is A an integer? If so, first of all, n must be a multiple of 30, so a >；; B

5) 1/3

All possibilities: BB BG GB GG

If it is already known that one of them is a boy, then there are only three possibilities for BB BG GB, so taking BB is 1/3.