Cho tam giác ABC vuông tại A có C=30° Đường cao AH lấy D thuộc HC Sao cho HD=HB . Qua C kẻ CE vuông góc với AD. a, Chứng minh rằng: tam giác ABH= tam giác ADH. b, Chứng minh ABC đều. c, Chứng minh: AH= CE .d, Gọi I là giao điểm củ AH và CE. Chứng minh rằng ID⊥AC

Suppose there is a simple index of three stocks, stock abc, stock xyz, and stock qrs. stock abc opens on day 1 with 4000 shares at $3.15 per share. stock xyz opens on day 1 with 5000 shares at $4.30 per share. stock qrs opens on day 1 with 6000 shares at $4.60 per share. the price of stock abc on day 8 begins at $3.50. the price of stock xyz on day 8 begins at $3.90. stock qrs opens on day 8 with a price of $4.50 per share. assume that each stock has the same number of shares that it opened with on day 1. what is the rate of change of this simple index over 1 week?

An appliance store sells a washer-dryer combination for $1800. if the washer costs $300 more than the dryer, find the cost for each appliance.

The volume of a box varies directly with its length if a box in the group has a length of 30inches and k=24 what is its volume