Answer:
Step-by-step explanation:
y₂₋y₁ / x₂-x₁ if you have two points you can plug them in and find the slope using this.
If it is on a graph you can look at two points and count the rise over run, for example if one point is (0, 0) and another is (2, 3) then from the first point it goes up 2 and over 3, so the slope would be 2/3
Since we have a cubic root, we're interested in factoring cubes inside the root, so that we can take them out. If we factor 648, we have

So, we have
![3x\sqrt[3]{648 x^4 y^8} = \sqrt[3]{3\times 6^3\cdot x^3\cdot x \cdot y^6\cdot y^2}=3x\cdot 6\cdot x\cdot y^2\sqrt[3]{3\cdot x\cdot y^2}](https://tex.z-dn.net/?f=3x%5Csqrt%5B3%5D%7B648%20x%5E4%20y%5E8%7D%20%3D%20%5Csqrt%5B3%5D%7B3%5Ctimes%206%5E3%5Ccdot%20x%5E3%5Ccdot%20x%20%5Ccdot%20y%5E6%5Ccdot%20y%5E2%7D%3D3x%5Ccdot%206%5Ccdot%20x%5Ccdot%20y%5E2%5Csqrt%5B3%5D%7B3%5Ccdot%20x%5Ccdot%20y%5E2%7D)
And the result simplifies to
![18x^2y^2\sqrt[3]{3xy^2}](https://tex.z-dn.net/?f=18x%5E2y%5E2%5Csqrt%5B3%5D%7B3xy%5E2%7D)
#1.
Here what you do is cross multiply.

#2.
Same as #1, just cross multiply.

You get the gist?