C I think I solved it and that's what I got.
I am WHITE, and only speak inglish because I am a 7th grader, only speak snipets of spanish, and not fluent. If you could translate, I would be happy to help you with your question.=)
We are given with 90<x<180 degrees and asks for the value of sin(x/2), cos(x/2) and tan(x/2). We just substitute the maximum and minimum angle to the equations. sin (180/2) is equal to 1 and sin (90/2) is equal to

to 1. cos (x/2) is equal to 0≤y≤<span>

. tan (x/2) is equal to 1 to infinity. </span>
1) Rational numbers are the numbers which can be expressed as the fraction.
In mathematical form, you can say: anything like: p/q (where, q≠ 0)
2) An Irrational number is the number which can't be expressed in the form of fraction, it repeats upto infinite digits.
Hope this helps!
<span>For a system of equations to have infinitely many solutions, the equations have to be lineary dependent, (i.e. one of the equations is a multiple of the other equation). For the given equation to have infinitely many solutions, the second equation have to be a multiple of the first equation.
The first equation can be rewritten as y - 2x = -5
The second equation is the first equation multiplied by 2, i.e. 2(y - 2x= -5) = 2y - 4x = -10
Therefore, the correct answer is -10 (option a).</span>