Answer:
A.
Step-by-step explanation:
Take a look at what happens when squaring either of these...

Notice a couple of patterns.
1. The last term has a positive coefficient. That rules out answer choices C and D.
2. The coefficient of the middle term is either
. So what are <em>a</em> and <em>b</em>? <em>a</em> is the square root of the x^2 term and <em>b</em> is the square root of the y^2 term.

The middle coefficient needs to be either +30 or -30. The answer is choice A.
Answer:
26
Step-by-step explanation:
18,23,24,28,29,30
(6 in total + 1)/2=3.5.
- the number which is 3.5 is between 24 and 28.
- middle number between these two is 26.
Answer:
x = 12
Step-by-step explanation:
5+x2 = 2x2+13
5+x2 = 4+13
5+x2÷2 = 17
5-5+x = 17-5
x = 12
Answer:
53.2
Step-by-step explanation: