Answer:
B)
Step-by-step explanation:
225x^2 - 1=
(15x)^2 - 1^2=(*)
(15x-1)(15x+1)
A^2 - B^2 =(A-B)(A +B)............. (*)
Answer:

Step-by-step explanation:
The total surface area of a cone is given by :

Put r = 2r and l = 2l in the above formula

Hence, the total surface area of the cone is
.
Answer:
x≥9
Step-by-step explanation:
Pretend the Less than or equal to sign is just an equals sign
-7x+7=-56 Solve:
-7x=-56-7
-7x=-63
For the last step, if you divide a negative number, the Sign switches. So not the sign is greater than or equal to.
x>=9