What is 21-3? how can we. solve this using mental math?

What is the measure of x, in degrees

(10. in the figure, a aabc is drawn tocircumscribe a circle of radius 3 cm ,such thatthe segments bd and dc are respectively oflength 6 cm and 9 cm. find the length ofsides ab and ac.

1. which answer is the solution set to the given inequality? 2x+6< 8 a. x e (-∞,1) b. x e [1,∞) c. x e (1,∞) d. x e (-∞,1] 2. which answer represents the given compound inequality in interval notation? x≥12 or x< -4 a. x e [-4, 12) b. x e (-∞, -4) u [12,∞) c. x e (-∞, -4] u (12,∞) d. x e (-4,12] 3. which answer is the solution set of the given compound inequality? 7> x+6 or x-2≥3 a. x e (-∞, 1) u [5,∞) b. x e (1, 5] c. x e (-∞, 1) ∩ [5,∞) d. x e [1,5) 4. which conjunction or disconjunction is equivalent to the given absolute value inequality? |x+3|> 12 a. x+3> 12 and x+3< -12 b. x+3< 12 and x+3> -12 c. x+3< 12 or x+3> -12 d. x+3> 12 or x+3< -12