Answer:
![\large\boxed{x=\dfrac{\pi}{6}\ \vee\ x=\dfrac{5\pi}{6}\ \vee\ x=\dfrac{7\pi}{6}\ \vee\ x=\dfrac{11\pi}{6}}](https://tex.z-dn.net/?f=%5Clarge%5Cboxed%7Bx%3D%5Cdfrac%7B%5Cpi%7D%7B6%7D%5C%20%5Cvee%5C%20x%3D%5Cdfrac%7B5%5Cpi%7D%7B6%7D%5C%20%5Cvee%5C%20x%3D%5Cdfrac%7B7%5Cpi%7D%7B6%7D%5C%20%5Cvee%5C%20x%3D%5Cdfrac%7B11%5Cpi%7D%7B6%7D%7D)
Step-by-step explanation:
![12\cos^2x-9=0\qquad\text{add 9 to both sides}\\\\12\cos^2x=9\qquad\text{divide both sides by 12}\\\\\cos^2x=\dfrac{9}{12}\\\\\cos^2x=\dfrac{9:3}{12:3}\\\\\cos^2x=\dfrac{3}{4}\to\cos x=\pm\sqrt{\dfrac{3}{4}}\\\\\cos x=\pm\dfrac{\sqrt3}{2}\\\\\text{Look at the picture}\\\\x=\dfrac{\pi}{6}\ \vee\ x=\dfrac{5\pi}{6}\ \vee\ x=\dfrac{7\pi}{6}\ \vee\ x=\dfrac{11\pi}{6}](https://tex.z-dn.net/?f=12%5Ccos%5E2x-9%3D0%5Cqquad%5Ctext%7Badd%209%20to%20both%20sides%7D%5C%5C%5C%5C12%5Ccos%5E2x%3D9%5Cqquad%5Ctext%7Bdivide%20both%20sides%20by%2012%7D%5C%5C%5C%5C%5Ccos%5E2x%3D%5Cdfrac%7B9%7D%7B12%7D%5C%5C%5C%5C%5Ccos%5E2x%3D%5Cdfrac%7B9%3A3%7D%7B12%3A3%7D%5C%5C%5C%5C%5Ccos%5E2x%3D%5Cdfrac%7B3%7D%7B4%7D%5Cto%5Ccos%20x%3D%5Cpm%5Csqrt%7B%5Cdfrac%7B3%7D%7B4%7D%7D%5C%5C%5C%5C%5Ccos%20x%3D%5Cpm%5Cdfrac%7B%5Csqrt3%7D%7B2%7D%5C%5C%5C%5C%5Ctext%7BLook%20at%20the%20picture%7D%5C%5C%5C%5Cx%3D%5Cdfrac%7B%5Cpi%7D%7B6%7D%5C%20%5Cvee%5C%20x%3D%5Cdfrac%7B5%5Cpi%7D%7B6%7D%5C%20%5Cvee%5C%20x%3D%5Cdfrac%7B7%5Cpi%7D%7B6%7D%5C%20%5Cvee%5C%20x%3D%5Cdfrac%7B11%5Cpi%7D%7B6%7D)
Answer:
Yes it is proportional because if the line kept going, it would pass through the origin. Fora line to be proportional, it must pass through the origin.
Origin= (0,0)
Step-by-step explanation:
Brainliest?
Answer:
The price of the piano is $311.69
1 x 4 = 4
4 x 5 = 20
20 x 6 = 120
120 x 7 = 840
So the answer is 840
It would be 1444
hope this helps