To figure out the degrees, you would create a ratio.
Since there are 360 degrees in your circle, that would be representative to 100 (because both are the total of what you want to find), and x would be representative to what degrees 65 is equal to.
your ratio should look like,
65/100=x/360
cross multiply and get
65(360)=100x
23400=100x
x=234
It looks hard to read like this, but if you write it out on your paper it should make more sense!
Answer 28 because you plug it in for your answer.
Mentally
As they are numbers which you can do mental math with since they are whole numbers.
You will pay $292.5 for a item with original price of $390 when discounted 25%. In this example, if you buy an item at $390 with 25% discount, you will pay 390 - 97.5 = 292.5 dollars
I factor it because you can't simplify
2x-8=2(x-4)
X^2+5x+4=(x+1)(x+4)
X^2-16=(x-4)(x+4)
X^2+8x+16=(x+4)(x+4)
