What is the simplified form of the expression 3²+7-y²-5-2y²-1

Ineeeeed this is due tomorrow and i dont know the answer can you find all the exponents

Aclassmate thinks that solving a system by graphing gives an exact answer when the lines appear to cross at a grid point, but only an approximate answer when they don't. explain why this isn't true.

Newtons second law says force(f) is equal to mass (m) times avceration (a) a scientist wamts to calculate the force of an objecy where the acceleration of gravity (g) is 9.8m/ s2 use the function to calculate the force of an object with a mass73( m) of 0.29 kilograms