Mary spent $16.87 at the bookstore. She paid with a $20 bill. How much is her change?

Can someone me i’m confused. will give brainliest and a whole bunch of points

Sundar used linear combination to solve the system of equations shown. he did so by multiplying the first equation by 5 and the second equation by another number to eliminate the y-terms. what number did sundar multiply the second equation by? 2x+9y=41 3x+5y=36

Write the equation in logarithmic form 8^x=64