Step-by-step explanation:

Answer:
x = 15
Step-by-step explanation:
Assuming 3x and x-60 are in degrees, you can use:
cos(a) = sin(a+90)
To rewrite the equation as:
sin(3x) = sin(x-60+90)
sin(3x) = sin(x+30)
3x = x+30
2x = 30
x = 15
But, solving 3x = x+30 which simplifies to x=15 is not the only solution to this equation, as you can see in below picture. Finding all solutions is a bit more work, but maybe that is not required in your case.
Easy peasy
the midpoint between

and

is

just average them
so given that (3,5) is the midpoint of (-4,5) and (x,y)

so by logic

and

times both sides by 2 for everybody
-4+x=6 and 5+y=10
add 4 to both sides for left one and minus 5 from both sides for right
x=10 and y=5
the coordinate of point C is (10,5)
the x coordinate is 10
Answer:
DE=16
Step-by-step explanation:
I took the test and it's right!
159 seconds. The 1st two slices of bread will take 60 seconds to toast. 20 second to put in and out. And 6 seconds to turn them over. The 3rd piece will take 60 seconds to toast, 10 seconds to put in and out, and 3 seconds to turn over. 86 seconds + 73 seconds= 159