the picture in the attached figure
we know that
∠Y+∠Z=90°
∠Z=2b+6 ∠Y=3b-1
so
(2b+6)+(3b-1)=90----> 5b+5=90----> 5b=85----> b=17°
∠Z=2b+6---- 2*17+6-----> ∠Z=40°
∠Y=3b-1---> ∠Y=3*17-1---> ∠Y=50°
angle Y and W are supplementary angles
so
∠Y+∠W=180---------> ∠W=180-∠Y------> ∠W=180-50----> ∠W=130°
angle X and Z are supplementary angles
so
∠X+∠Z=180---------> ∠X=180-∠Z-----> ∠X=180-40°----> ∠X=140°
the answers are
a) ∠Z=40°
b) ∠Y=50°
c) ∠W=130°
d) ∠X=140°