Which equations are quadratic? Check all that apply.
A. 2x2 + 3 = 0
B. x3 – 7x+ 1 = 0
C. 4x2 + 8x = 0
D. 5x – 12 = 0
E. x2 + 2xy + 9 = 0
F. x2 + 2x + 7 = 0

1. If it is intersection then it SHOULD be included in both the sets right? Now we know that odd numbers from 1-100 but the second set are multiples of 5 from 50-150! So we mainly need to look for common numbers which are ODD and are a MULTIPLE OF 5 BETWEEN 50 - 100!! So A={51,53,57,59,6199} B={55,60,65,7095} [We stop till 100 because set A has no such element] So what is A ∩ B here? A ∩ B = {All odd numbers and multiples of 5 between 50 - 100}