Answer:
(9g - 6f)(9g + 6f)
Step-by-step explanation:
81g^2 - 36f^2 =
(9g)² - (6f)² =
(9g - 6f)(9g + 6f)
Answer: 
You can write this as (-infinity, 7) if you aren't able to use the infinity symbol.
====================================================
Explanation:
Think of x < 7 as writing 
So x is between negative infinity and 7, excluding both endpoints.
To write
in interval notation, we write
The curved parenthesis tell us to exclude the endpoint.
Alternate angles - happy to help!
B
calculate the slopes m of the 2 lines using the gradient formula
m = (y₂ - y₁ ) / (x₂ - x₁ )
with (x₁, y₁ ) = C(- 2, 4) and (x₂, y₂ ) = D(0, - 4 )
=
=
= - 4
repeat with (x₁, y₁ ) = F(- 4, 0 ) and (x₂, y₂ ) = G(4, 2 )
=
=
= 
The 2 lines are perpendicular because their slopes are negative reciprocals
Step-by-step explanation:

By simplifying the right side of the equation, we come up with
, or D