In the Figure, the Two Long Straight Wires Are Separated $d = 0.40 \mathrm {~m}$

In the figure, the two long straight wires are separated by a distance of $d = 0.40 \mathrm {~m}$ . The currents are $I _ { 1 } = 1.0 \mathrm {~A}$ to the right in the upper wire and $I _ { 2 } = 8.0 \mathrm {~A}$ to the left in the lower wire. What are the magnitude and direction of the magnetic field at point $P$ , that is a distance $d / 2 = 0.20 \mathrm {~m}$ below the lower wire? $\left( \mu _ { 0 } = 4 \pi \times 10 ^ { - 7 } \mathrm {~T} \cdot \mathrm { m } / \mathrm { A } \right)$