In δabc, if m `/_a` = m`/_c`, m`/_b` = ß (where ß is an acute angle), and bc = x, which expression gives the length of b, the side opposite `/_b` ? a. `sqrt(x^2 - 2x^2 cos beta)` b. `sqrt(x^2 - (1 - cos beta))` c. `sqrt(2x^2 (1 - cos beta)^2)` d. `sqrt(2x^2 (1 - cos beta))` plz ! 10

D. is the length of  b, the side opposite to .

Explanation:

According to the line of cosines, length of one side when opposite angle and two other sides are given.

c^2=a^2+b^2-2 ab cos C, where a,b, c are the sides of triangle while C is the opposite angle of side c.

Here, a=b=x(because ) , c= length of b (that is side AC) and

Thus,  

Therefore,  length of b =

problem:

f(x) = - 2/3x + 5; f(5/2)

substitute 5/2 in for x:

f(5/2) = -2/3(5/2) + 5

simplify the right side:

f(5/2) = -5/3 + 5

f(5/2) = 10/3

f(5/2) = 10/3

i hope this !