Simple maths question involving sohcahtoa
an explanation would be

x=30

Step-by-step explanation:

x is the reference angle. the sides provided are the adjacent (12cm) and the opposite (7cm) which means we have to use tangent.

tan(x)=7/12

(x)=atan(7/12)

(x)=30

x = -4

step-by-step explanation:

- 20 - 4(x + 3) = 4x

=> -20 - 4x - 12 = 4x

=> - 32 -4x = 4x

=> -32 = 4x + 4x

=> - 32 = 8x

=> -32/8 = x

=> -4 = x