Answer:
Step-by-step expThis is the concept of trigonometry, the value of x will be calculated as follows;
sin theta=[opposite]/[hypotenuse]
theta=x
opposite=16 units
hypotenuse=21 units
thus;
sin x=16/21
hence;
x=arcsin(16/21)
x=49.63
x=50 (to the nearest degrees)
Now box is 3/4 full
3/4 = 3/4*1
3/4 = 3/4 * 3/3 = 9/12
Box is 9/12 full after heba ate 1/12 of a box of cereal
Initial fraction will be 9/12+1/12
=10/12= 5/6
First join the log4 on the left:
log4( x*(x-3) = log4(-7x+21)
Then x = -7, works: -7*(-10)=70 = -7*(-7)+21
x=-3, 18 = 42, does not work
x=3 0=0 works,
However, when one puts x = -7 in the *original* exression, log4(-7) or log4(-10) do not exist (you know why?). So x= -7 is extraneous.
Now x=3 gives log4(0) on the left and right, which does not exist.
So, C is the answer, both are extraneous. Seem to work but indeed don't work in the *original* equation
