Answer:
18) 6x^2-7x-5
19) 20x^2+17x-63
20) 18x^2-20x+2
21) 5x^2+42x+16
Step-by-step explanation:
Perimeter=length×breadth
18) (3x-5)(2x+1)
=6x^2+3x-10x-5
=6x^2-7x-5
19) (4x+9)(5x-7)
=20x^2-28x+45x-63
=20x^2+17x-63
20) (18x-2)(x-1)
=18x^2-18x-2x+2
=18x^2-20x+2
21) (5x+2)(x+8)
=5x^2+40x+2x+16
=5x^2+42x+16
Answer:
im pretty sure its B, i hope it helps
Step-by-step explanation:
We have the formula to compute the probability of having exactly k successed over n trials, given a probability p of success (and implicitly a probability 1-p of failure), which is

Now, the probability of at least 3 successes is the union of the following event: exactly three successes,exactly four successes and exactly five successes.
We can compute their probability and sum them:
So, the answer is about 36.79%