Does anyone know how to do any of these problems? My notes are no help and none of my classmates know what to do either.

Girardo is using the model below to solve the equation . girardo uses the following steps: step 1 add 4 negative x-tiles to both sides step 2 add 1 negative unit tile to both sides step 3 the solution is which step could be adjusted so that gerardo's final step results in a positive x-value? in step 1, he should have added 4 positive x-tiles to both sides. in step 1, he should have added 3 negative x-tiles to both sides. in step 2, he should have added 4 negative unit tiles to both sides. in step 2, he should have added 1 positive unit tile to both sides.

Combine like terms to make a simpler expression 3z+z

Asmall book publisher knows that 26 books weigh 41 lbs. how much do 40 books weigh?