h(x)=x^2+2x-1,
find h(x+9)-h(x) to do this you plug in the values.
h(x+9) = (x + 9 )^2 + 2(x + 9) - 1 I multiplied (x+9)(x+9) for the first three terms and distributed s across the two terms in the parenthesis.
h(x+9) = x^2 + 18x + 81 + 2x + 18 - 1
h(x+9) = x^2 + 20x + 98 now you have to take this result and subtract h(x) from it
h(x+9) - h(x) = x^2 + 20x + 98 - (x^2 + 2x -1)
h(x+9) - h(x) = x^2 + 20 x + 98 - x^2 - 2x + 1
h(x+9) - h(x) = 18x + 99