The height of a stack of books, h inches is directly proportional to the number of books, n . the height of a stack of 10 books is 12 inches.
-find the constant of proportionality
-write and equation that relates to handn
-find the height of a stack of 24 books

Y=kx is the direct variation formula. Inserting the information and variables from this scenario we get h = kn.
12 = k*(10) First solve for 'k', the constant of proportionality by dividing by 10.
1.2 = k
Next write the equation using this k and the h & n.
h = 1.2*n
Now we want to find the height if we have 24 books so plug 24 in for n.
h = 1.2 * 24
h = 28.8 inches

4+2=-2. 1+2=3. y=-2/3x+b. 2=4/3+b. 2/3=b. the answer is y= -2/3x+2/3