9) We can see that the sticks follow an aritmetic serie, where in each step he increase 7 sticks, and we know that the first pattern has 12 steacs so the 91 patern will have:

10) Now we can made a linear equation for the squares and the triangles, So first we will work with the squares, so we can see that they increas 1 by 1 so the slope will be equal to 1 and the intercept will be 0,0 so

So if we are in our first pattern x=1 and y =1, if we are in our second pattern x=2 and y=2 so this is true for the squares.
And for the triangle they are increasing 2 by 2 so the equation will be:
