For each pair of signals x(t) and h(t) given below, find the convolution y(t) = x(t)*h(t). In each case sketch the signals involved in the convolution integral and determine proper integration limits

y1 = e⁻⁴ˣ, y2 = xe⁻⁴ˣ, y3 = x²e⁻⁴ˣ