preciouslove: (4x2 - 5x - 2)(x2 + 5x + 2)
You have to know that you need to take the 4x
2 and multiplicate it by x
2, after that by 5x, and finaly by 2, and you do the same thing whit the second factor and the third.
You'll have this answer:
4x
4 + 20x
3 + 8x
2 - 5x
3 - 25x
2 + 10x - 2x
1 -10x - 4
Now, you need to simplicate the answer. At this point, you need to locate the same exponent to all X's. you have x
4, x
3, x
2, x. Simplificate the equation.
Know that x
4, x
3, x
2, x ARE NOT THE SAME THINGS, they are like apple, banana and orange!
4x
4 + 15x
3 - 17x
2 -4
+142 
