Assuming that you ment- (18*9)/3d where d=3 you would follow PEMDAS-
Parentheses
Exponents
Multiplication-Division (in order from right to left)
Addition-Subtraction (in order from right to left)
1. Parentheses- (18*9)=162
2. Solve your variables- 3d (3*3)=9
Giving you- 162/9
3. Solve-162/9=18
First step
12 x 1.3
Second step
15.6 x 7.5
The answer is 117 :)
Same as any other midpoint of line segment or two points, it is the average of the two points x and y coordinates...
mp=((x1+x2)/2, (y1+y2)/2)
mp=((-6+16)/2, (-9+5)/2)
mp=(10/2, -4/2)
mp=(5, -2)