The function y = loga (x2 + 2x-3), when x = 2, Y > 0, then the monotone decreasing interval of this function is () A. (-∞,-3)B. (1,+∞)C. (-∞,-1)D. (-1,+∞)

The function y = loga (x2 + 2x-3), when x = 2, Y > 0, then the monotone decreasing interval of this function is () A. (-∞,-3)B. (1,+∞)C. (-∞,-1)D. (-1,+∞)


When x = 2, y = loga 5 > 0, a > 1. From x2 + 2x-3 > 0 {x < - 3 or X > 1, it is easy to see that the function T = x2 + 2x-3 decreases on (- ∞, - 3), so the function y = loga (x2 + 2x-3) (where a > 1) also decreases on (- ∞, - 3)



Factorization: (1) 2A (a-b) - B (B-A) & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; (2) - a4b4 + 8a2b2-16


(1) The original formula = 2A (a-b) + B (a-b) = (a-b) (2a + b); (2) the original formula = - (a2b2-4) 2 = - (AB + 2) 2 (ab-2) 2



- 2A (a + b) + B (a + b) factorization!


﹣2a(a+b)+b(a+b)
=(b-2a)(a+b)