y = W x + b = [ w 11 ⋯ w 1 n ⋮ ⋱ ⋮ w m 1 ⋯ w m n ] [ x 1 ⋮ x n ] + [ b 1 ⋮ b m ] \mathbf{y} = W\mathbf{x} + \mathbf{b} = \begin{bmatrix} w_{11} & \cdots & w_{1n} \\ \vdots & \ddots & \vdots \\ w_{m1} & \cdots & w_{mn} \end{bmatrix} \begin{bmatrix} x_1 \\ \vdots \\ x_n \end{bmatrix} + \begin{bmatrix} b_1 \\ \vdots \\ b_m \end{bmatrix} y=Wx+b= w11⋮wm1⋯⋱⋯w1n⋮wmn x1⋮xn + b1⋮bm