What is the polynomial in (d-1)(5d-4)

Question

How would i solve using the so called FOIL method in this equation?

Answer 1

Everything moves from outer to inner: multiply the first number (or letter) by the first letter in the second set of ( )'s, then take the first (d) by the outer number, then move to the second number, and so forth:

#1 step: d*5d

#2: d*-4

#3: -1*5d

 #4: -1*-4

 

Now, put them all together in one long equation:

5d^2 -4d - 5d + 4

 

Now, solve for d