2? + 8x + 12 = 0 in expanded form​

In factoring by grouping, what would you have for step 3 for the following? step 1: x^3 +5x^2 +4x+20 step 2: x^2 (x+5)+4(x+5) step 3: ?

How to use order of operation in 20 divide by 4 multiply 5 = 1

The length of the line segment joining the midpoints of sides ab and bc of the parallelogram abcd is 10. find the length of diagnol ac