Use the difference of two squares identity to factor each of the following expressions. (a) x²-81 (b) (3x+y)² -(2y)² (c) 4-(x-1)² (d) (x+2)²-(y-2)²

a)

b)

c)

d)

Explanation:

Factor the expression using difference of two squares.

Formula:

Part a)  x²-81

write 81 as perfect square.

Part b) (3x+y)² -(2y)²

Part c) 4-(x-1)²

write 4 as perfect square,

Part d) (x+2)²-(y-2)²

step-by-step explanation:

answer: first option i.e. 'a' is correct.

step-by-step explanation:

since we have given that

number of minutes to wrap a small gift box = 4 minutes

we need to find the number of gifts to be wrapped in 5 minutes

since there is a direct variation, as the number of minutes will increase with   number of gifts to be wrapped.

so, let the number of gifts to be wrapped in 5 minutes be x.

so, it becomes,

hence, first option 'a'   is correct.