Let r = ln x, s = ln (x2 + 10), t = ln (x4 + 9), u = ln 10, v = ln 9. rewrite the expression below in a form with no logarithm of a product, quotient or power. then use some, or all, of the letters r, s, t, u, v, and x to enter this new form of the logarithm in the answer blan