Answer:
x=3, -1/7
Step-by-step explanation:
7x^2-20x-3=0
Factor.
(x-3)(7x+1)=0
x-3=0 ⇒ x=3
7x+1=0 ⇒7x=-1 ⇒x= -1/7
Answer:
The diameter is any straight line that passes through the center of the circle, which endpoints can lie on. The radius is half the diameter. They help us find the circumference of a circle
Answer:
Gọi AH là đường cao kẻ từ A đến BC
Xét tam giác AHC vuông tại H
Suy ra AH = HC. cotA= 9.cot35° = 12,9
Xét tam giác AHB vuông tại H
Suy ra BH = AH.tanA = 12,9.tan61°=23,37
Ta có BC= HC+ HB= 9+23,27 =32,27
Diện tích tam giác ABC = 1/2 × AH ×BC= 1/2 ×12,9×32,27=208,1415
Answer:
Cooking will be shortest when the househusband covers the beef stew with the heavy lid.
Step-by-step explanation:
The explanation for this is that water boils at 100°C at normal atmospheric pressure & it remains at that temperature until all the water evaporates as steam; the temperature can then go higher in steam form.
So, if he leaves the pan uncovered the pressure above the beef stew will be the atmospheric pressure and the temperature of the stew will not pass the 100°C mark and the food cooks at 100°C.
If he places a light lid on top, the pressure will build up & the temperature at which water remains liquid is a bit higher, but eventually the steam will push the lid to escape thereby releasing pressure & reducing the temperature.
If he puts a heavy lid on the pan the pressure can build up the highest and the temperature of the water in the stew will stay the highest ensuring the fastest cooking.
Basically, the heavier the lid, greater the pressure in the pan. As the pressure gets greater, the saturation temperature at which water starts boiling will be higher. And higher boiling temperatures mean shorter cooking times.
35 because if you half the amount of salads he's eaten (seeing as he eats one burger for every two salads) then the extra one is the first salad in the cycle.
