Solution:
iv) Given equation: 
Since we are given two variables, we need to split the original expression into two quadratic expressions as
Factoring x first:
= 
= 
Factoring y now:
= 
= ![-1[ y(y+1) + 1(y+1)]](https://tex.z-dn.net/?f=-1%5B%20y%28y%2B1%29%20%2B%201%28y%2B1%29%5D)
= ![-1 [(y+1)(y+1)]](https://tex.z-dn.net/?f=-1%20%5B%28y%2B1%29%28y%2B1%29%5D)
= 
Therefore, the original expression becomes
Answer:
10
Step-by-step explanation:
Using $A^2 + B^2 = C^2$, we know that $A = 6$ and $B = 8$. $8^2 = 64$ and $6^2 = 36$. $64 + 36 = 100$, and $√100 = 10$.
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}
