Answer:
x^2-19x+90
Explanation:
For multiplying binomials, what you have to do is multiply the two terms from first set with both terms from the second set. For example, in this situation, you take x and multiply it with both x and -10, and then you take -9 and multiply it with both x and -10. You will end up with x^2-10x-9x+90. Finally, you have to combine the like terms and you would end up with x^2-19x+90.