Lexi answers 45 questions correctly on a test and earns a 90%. How many questions were on the test?

(a) calculate the molarity of a solution that contains 0.0345 mol nh4cl in 400 ml of solution. (b) how many moles of hno3 are present in 35.0 ml of a 2.20 m solution of nitric acid? (c) how many milliliters of 1.50 m koh solution are needed to supply 0.125 mil of koh ?

What is sin 7x/4 ? i need on this urgent trig

What is the slope of the line that contains the points (-2,1) and (0,-3)