We want all x on one side, all t on the other.

Divide both sides by (x + 3) and multiply both sides by dt:

Divide both sides by t.

Integrate both sides.

Important: dx and dt must be on top of the fraction (i.e. in the numerator).

Take e to power of both sides:

(We let e^c = K, constant)

So x = Kt − 3 .

Typical solution and graph (letting K = 7)

x = 7t − 3