Thanks you can l have help

What number should be added to both sides of the equation to complete this square? x^2-10x=7

Amuffin recipe, which yields 12 muffins, calls for cup of milk for every 1 cups of flour. the same recipe calls for cup of coconut for every cup of chopped apple. to yield a batch of 30 muffins, how much flour will be needed in the mix?

How many solutions does the nonlinear system of equations graphed bellow have?