x\left(x+6\right)+4\left(x+5\right)
-2(-3y)
81:9 = x:22
distribution of (1/n)\sum_{i=1}^{n} X_i, where X_i has Normal distribution N(\mu, 1)
-x\left(11y+13z\right)
limit of a function
4(3x)
-\left(2p-3q\right)