Both triangles that are given (with right angles) lie in plane m, proving that AC is perpendicular to plane m. As angle acd is from a triangle that shares the common perpendicular, it too is a right angle
Answer:
17
Step-by-step explanation:
8+9 is 17
So, -(a-3b) becomes -1(a-3b). Then, this becomes 5a-1a+3b. There is +3b because there is a double negative. So, 5-1=4, so your answer is 4a+3b. Pls brainliest