Find (-5)(-2)(5)( - 1)(-4)

200. Multiply all starting from left to right

200

Step:
(-5)(-2)=10
10(5)=50
50(-1)=-50
(-50)(-4)=200

The sum of the interior angles of a triangle is 180 so to find x your equation would be (x+15)+(2x-20)+(2x)=180...once you solve this equation x should be 37...and now you just plug in 37 for x and solve for the angle measurments(37+15)=52(2(37)-20)=542(37)=74