Solution:x^2+3x-4=(x+4)(x-1)>0,
therefore, the x range is (-∞,-4)∪(1,+∞).
Answer:(-∞,-4)∪(1,+∞).[
1. (x−1)(5x+8)−2x+5
=(x)(5x)+(x)(8)+(−1)(5x)+(−1)(8)+−2x+5
=5x2+8x+−5x+−8+−2x+5
Combine Like Terms:
=5x2+8x+−5x+−8+−2x+5
=(5x2)+(8x+−5x+−2x)+(−8+5)
=5x2 + x + −3
2. (−2+5)(3x+9)
=9x+27
3. 2x+5−8x+12
=2x+5+−8x+12
Combine Like Terms:
=2x+5+−8x+12
=(2x+−8x)+(5+12)
=−6x+17
4. (−x+3)(−5x−2)
=(−x+3)(−5x+−2)
=(−x)(−5x)+(−x)(−2)+(3)(−5x)+(3)(−2)
=5x2+2x−15x−6
=5x2 − 13x − 6
firstly chain rule is dy/dx = dy/du * du/dx
a) y = 5u² + u - 1 hence dy/du = 10u +1
u = 3x +1 hence du/dx = 3
so dy/dx = 3(10u +1) {sub in u and expand}
b) y= u^-2 hence dy/du = -2u^-3
u=2x+3 hence du/dx = 2
so dy/dx= 2(-2u^-3) {sub in u}
