What is the solution to this equation 7x=21

7x=21

divide both sides by 7 to get x by itself

7x/7= 21/7

cross out 7 and 7 , divide by 7

then becomes 1*1*x= x

x= 21/7

x= 3

i dont know it

step-by-step explanation:

hope it you

step-by-step explanation:

sin(7pi/6 - pi/3)  

= sin(7pi/6 - 2pi/6)  

= sin(5pi/6)  

= sin(pi - pi/6)  

= sin(pi/6)  

= 1/2  

sin 7pi/6 - sin pi/3  

= sin (pi + pi/6) - sin pi/3  

= -sin pi/6 - sin pi/3  

= -1/2 - sqrt(3)/2  

= -(1+sqrt(3))2