\(\overrightarrow{ F }+5 \hat{ i }-6 \hat{ i }+7 \hat{ j }-8 \hat{ j }=0\)
\(\overrightarrow{ F }=\hat{ i }+\hat{ j },|\overrightarrow{ F }|=\sqrt{2}\)
Angle with X-axis: \(\tan \theta=\frac{ y \text { component }}{ x \text { component }}=\frac{1}{1}\)
\(\theta=45^{\circ}\)