Show that 6=4x+5y and 10x=8y-5 are perpendicular.​

(a) (8%) compute the probability of an even integer among the 100 integers 1! , 2! , 3! , until 100! (here n! is n factorial or n*(n-1)*(n-2) *… 1) (b) (16%) compute the probability of an even integer among the 100 integers: 1, 1+2, 1+2+3, 1+2+3+4, …., 1+2+3+… + 99, and 1+2+3+… + 100

In the geometric progression –3, 12, −48… what term is 3,072?

Find two numbers if their sum is 91 and the ratio is 6: 7?