Yes, xy is the same as yx, but should always be written as xy.
Area of a trapezoid = 0.5*(sum of parallel sides)*height
It depends on where arc XY is: on a circles, a parabola or some other curve; and what else you know about the curve.
Suppose the numbers are x and y. The sum of their reciprocals = 1/x + 1/y = y/xy + x/xy = (y+x)/xy = (x+y)/xy = 10/30 = 1/3
the sum of 3 times m and n
Suppose the two numbers are x and y. Then, the sum of THEIR reciprocals is 1/x + 1/y = y/xy + x/xy = (y + x)/xy = 7/25
Suppose the numbers are x and y Then the sum of their reciprocals is 1/x + 1/y = y/xy + x/xy = (y+x)/xy = 10/20 = 1/2
1/x+1/y y/xy+x/xy x+y/xy=12/24 12/24=1/2 1/2 is the answer.
|XZ| = |ZY| and |XZ| + |ZY| = |XY| That is, the length of XY is the same as the sum of the lengths of XZ and ZY, which are themselves the same as each other.
(x+y+z)*3= Using the 'Order of Operation' rules, the addition within brackets is done first, then the sum is multiplied by 3 (thrice means three).
(a + b)/(xy)