What is the equivalent factored form of 12x4 – 42x3 – 90x2? 6x(x – 5)(2x + 3) 6x2(x – 5)(2x + 3) 6x(x + 5)(2x – 3) 6x2(x + 5)(2x – 3)

B. Factor out x^2 first. 12*x^4-42*x^3-90*x^2=(x^2)*(12*x^2-42*x-90). See that 6 is a common divisor of 12, 42, 90, so factor out 6: (6x^2)*(2*x^2-7*x-15).Then factor (2x^2-7x-15) as (2x+3)*(x-5). So the original expression=(6x^2)(2x+3)*(x-5)