The equation cos(35°) = can be used to find the length what is the length of bc? round to the nearest tenth of bc

I’m really confused and need your assist me with this question i’ve never been taught

Find the vertex for the parabola given by the function ƒ(x) = −3x2 − 6x.

Astudent found the solution below for the given inequality. |x-9|< -4 x-9> 4 and x-9< -4 x> 13 and x< 5 which of the following explains whether the student is correct? -the student is completely correct because the student correctly wrote and solved the compound inequality. -the student is partially correct because only one part of the compound inequality is written correctly. -the student is partially correct because the student should have written the statements using “or” instead of “and.” -the student is completely incorrect because there is no solution to this inequality.