Find the linear approximation of the function f(x, y, z) = x2 + y2 + z2 at (4, 4, 7) and use it to approximate the number 4.022 + 3.992 + 6.972 . (Round your answer to five decimal places.) f(4.02, 3.99, 6.97) ≈

Cassie is traveling 675 miles today to visit her brother and his family. so far, she has stopped for gas three times. at the first stop, she put in 7.1 gallons of gas and paid $23.79. at her second stop, she put in 5.8 gallons of gas and paid $19.08. and, at the third stop, 6.6 gallons and paid $20.39. at which stop did casey pay the most for gas?

How to use order of operation in 20 divide by 4 multiply 5 = 1

I'm confused on this could anyone me and show me what i need to do to solve it.