a) To factorize this expression, we need to find two numbers that multiply to give 8 and add to give 6. The two numbers that fit this description are 4 and 2, so we can write the expression as x² + 6x + 8 = (x + 4)(x + 2).
b) To factorize this expression, we need to find two numbers that multiply to give 18 and add to give -9. The two numbers that fit this description are -6 and -3, so we can write the expression as x²-9x + 18 = (x - 6)(x - 3).
c) To factorize this expression, we need to find two numbers that multiply to give -9 and add to give -8. The two numbers that fit this description are -3 and 3, so we can write the expression as x² - 8x-9 = (x - 3)(x + 3).
d) To factorize this expression, we need to find two numbers that multiply to give -27 and add to give 6. The two numbers that fit this description are -9 and 3, so we can write the expression as x² + 6x-27 = (x + 9)(x - 3).