The difference between twice a number and half that number is 30. What is the number?

In the following diagram it is given that dec,ab || dc, ad || eb, and ad is congruent to bc. a)why isn't abc a parallelogram even though it has a pair of parallel sides and a pair of congruent sides b)explain why be must be congruent to bc. further explain what type of triangle this makes triangle abc and what it tells you about angle 1 and angle 2c) finally why must angle 3 be congruent to angle 1? further, explain why we know that angle 3 is congruent to angle 2

What is the result of adding the system of equations? 2x+y=4 3x-y=6

If a line is defined by the equation y = 5x + 2, what is the slope?