What are some sources of new mathematical symbols that have been widely used?

Consider the reflection of parallelogram pqrs across the line of reflection, . if rr' = 14, then rz = . if sx = 5, then = 5.

Adriveway is 60-feet long by 6-feet wide. the length and width of the driveway will each be increased by the same number of feet. the following expression represents the perimeter of the larger driveway: (x + 60) + (x + 6) + (x + 60) + (x + 6) which expression is equivalent to the expression for the perimeter of the larger driveway? a) 2(x + 66) b) 4x + 33 c) 4(x + 33) d) 4(x + 132)

According to the general equation for conditional probability if p(anb)=3/7 and p(b)=7/8 what is p(a i b)