How do I do this? I'm lost

Absolute value is a magnitude and is either positive or zero. Zero is neither positive nor negative. But the absolute value of any non-zero number can be thought of as it's distance from zero and it will always be positive.

Step-by-step explanation:

SOLVING EQUATIONS CONTAINING ABSOLUTE VALUE(S)

Step 1: Isolate the absolute value expression.

Step2: Set the quantity inside the absolute value notation equal to + and - the quantity on the other side of the equation.

Step 3: Solve for the unknown in both equations.

Step 4: Check your answer analytically or graphically.

okay so 15.15 *()5: +5/6

step-by-step explanation:

m∠a is 90°

m∠b is 40°