What is the coefficient of x^3 in the expansion of (2x-3)^5?
a) -5
b) 10
c) -120
d) -360
e) 720

309

Step-by-step explanation:

(2x-)^5

step 1

1 5 10 10 5 1

step 2

1(2x¹-3^0) 5(2x²-3^5) 10(2x³-3^4)

10(2x^4-3³) 5(2x^5-3²)

1(2x^0-3¹)

step 3

(2x) (10x²-243) (20x³-81) (20x^4-27)

(10x^5-9) (2-3)

step 4

2 -243-61-7 +1 -1=309

probability for j is 1/4

while

a is 1/6

a 4/6 = 9/12   not proportional

step-by-step explanation:

to find which are not proportional, we can use cross products

if it is true, they are proportional.   if it is not true, they are not proportional.

a 4/6 = 9/12

4* 12 = 6*9

48 = 54

not this is not proportional  

b 2/3 = 12/18  

2* 18 = 3 * 12

36 = 36

this is proportional

c 5/4 = 10/8  

5*8 = 4*10

40 = 40

this is proportional

d 7/5 = 35/25

7*25 = 5 * 35

175 = 175

is proportional