let's recall the graph of sin(x), is simply a sinusoidal line waving about, but its midline is at the x-axis, namely y = 0.
this equation is simply a transformation of it, the 1/2 changes the amplitude by half, midline stays the same though, the +3, moves the whole thing upwards, a vertical shift of 3, meaning the midline went from 0 to 3, y = 3.
Answer:
In a box and whisker plot, there is a rectangle (box) with a line in the middle of it. The middle is the mean. The interquartile values are the ends of the rectangle (the lower one -- 25% -- to the left and the higher one -- 75% -- to the right).
2(x-3)=7x-31
2x-6=7x-31
-7x -7x
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-5x-6=-31
+6 +6
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-5x=-25
Divide by -5
x=5
3x-2(x+5)=-3+18
15
3x-2(x+5)=15
3x-2x-10=15
x-10=15
+10 +10
--------------
x=25
You can solve this one by adding their rates, but you have to invert the numbers they give you to find the rate. Rate is measured in something per unit of time, and "per" indicates division. So the rates are: 1/3 of an hour (Sally) and 1/6 of an hour (Steve). So add the rates: 1/3 + 1/6 = 1/2. (1/3 is 2/6, and 2/6 + 1/6 = 3/6). Since their combined rate is 1/2 of a room in one hour, it takes them two hours to paint the room.
This answer makes sense: It takes Sally three hours by herself; with Steve's help, she's faster, but not THAT much faster, because he's pretty slow. You can often spot-check word problem answers like this by giving it a common sense once-over. If we came up with four hours, that would clearly be wrong: it should take her LONGER if she's getting help.
