The equation given in the question has one unknown variable in the ofrm of "x" and there is also a single equation. So it can be definitely pointed out that the exact value of the unknown variable "x" can be easily determined. Now let us focus on the equation given in the question.
x/35 = 7
x = 35 * 7
x = 245
So we can find from the above deduction that the value of the unknown variable "x" is 245. The correct option among all the options given in the question is option "B". I hope the procedure is not complicated for you to clearly understand.
The set X = { x , {x} } would, I think, fit the Bill
So its 2 elements
The base angles are congruent because it's an isosceles triangle the base angles would both equal 81
Here's a good rhyming rule to keep in mind.
Zero to four, you get no more.
Five to nine, move up one time.
With this rule you can see that there is a 5 at the end, therefor you should round up. Your number is 720.