How many times greater is the value of the 3 in 3,499 than in 6,399

Look at arnold's attempt to solve the equation for b: 3b = 12 b = 3 · 12 b = 36 describe the mistake that arnold made.

If f(x)=-x^2+6x-1 and g(x)=3x^2-4x-1,find(f+g)(x)

Write the equations in logarithmic form 7^3=343