2x^2+7x-5+(-8x^2-3x+5)=-6x^2+4x.
Answer: 51 notes span 6 octaves.
Step-by-step explanation:
The word "octave" is a Latin word that means "eight".
In an instrument, Each octave is made up of 8 musical notes.
If we have 51 notes , the number of octaves can be made in it = 
![=6.375\approx6\ \ \ \ \ \text{[Rounded to the nearest whole number]}](https://tex.z-dn.net/?f=%3D6.375%5Capprox6%5C%20%5C%20%5C%20%5C%20%5C%20%5Ctext%7B%5BRounded%20to%20the%20nearest%20whole%20number%5D%7D)
Hence, 51 notes span 6 octaves.
T= 8/100 × $8.29
t= $66.32/100
t= $0.66 rounded to the nearest penny