So firstly, the three terms share a GCF of x, so factor that out: [tex] x(20x^2+33x+7) [/tex]
Next, I'm going to be factoring by grouping. But first, what two terms have a product of 140x^2 and a sum of 33x? That would be 28x and 5x. Replace 33x with 5x + 28x: [tex] x(20x^2+5x+28x+7) [/tex]
Now factor 20x^2 + 5x and 28x + 7 separately, make sure that they have the same quantity on the inside: [tex] x[5x(4x+1)+7(4x+1)] [/tex]
Now you can rewrite the expression as [tex] x[(5x+7)(4x+1)] [/tex] , which is your final answer.