Solve i don't understand it with letters

∠1 and ∠2 are complementary. ∠1=x°∠2=(3x+30)° select from the drop down menu to correctly answer the question. what is the value of x? . a.15 b.25 c.30 d.40 e.55

Use the x-intercept method to find all real solutions of the equation. -9x^3-7x^2-96x+36=3x^3+x^2-3x+8

Gregory draws a scale drawing of his room. the scale that he uses is 1 cm : 4 ft. on his drawing, the room is 3 centimeters long. which equation can be used to find the actual length of gregory's room?