Expand (x+4)(x-4)=33 to give values of x

Use FOIL to expand the brackets. To do this, we start by multiplying the FIRST value in each bracket which in this case is x so we get x^2. Then we multiply the OUTSIDE two values, so here that is x and -4 so we get -4x. Then we multiply the INSIDE two values which is x and 4 so we get 4x and then finally the LAST two values giving us 4x-4 which is -16. Then we add up all the four values so we get:x^2 - 4x + 4x - 16 = 33We can then simplify this down by cancelling out the +4x and the -4x so we get:x^2 - 16 = 33Then we carry the '-16' over to the other side of the = sign because we are grouping like terms in order to simplify. To get rid of the '-16' on the left we have to add 16. Whatever we do to one side of the = we have to do to the other so we add 16 to the '33' on the other side giving us 49 so we know x^2=49 therefore x must equal 7 or -7