Write the product in standard form: (3y-5)(3y+5)

9y^2 - 25

Step-by-step explanation:

This is the product of the sum and difference of two squares:

(a - b)(a + b) = a^2 - b^2 (a formula well worth memorizing)

Therefore, (3y - 5)(3y + 5) = 9y^2 - 25, which is in standard form.

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

i need a picture

step-by-step explanation: