Solve 2(4x + 3) < 5x + 21. {x | x < 9} {x | x > -5} {x | x > -9} {x | x < 5}

, the first two terms and the last two terms:f(x) = (x3 - x2) + (-4x + 4)We factor out x2 in the first and 4 out of the second:f(x) = x2(x - 1) + 4(-x + 1)Looks at the second half. if we factor out a -1 as well, then our factors will have the same parentheses:f(x) = x2(x - 1) - 4(x - 1) Now we put the factored out parts in their own parentheses:f(x) = (x2 - 4)(x - 1)Take a look at the first parentheses set--we have a subtraction of two squares, which means that too can be factored:f(x) = (x + 2)(x - 2)(x - 1)