Answer:
9a2 − 30a + 25
Step-by-step explanation:
Perfect square trinomials follow these forms:
[tex](a+b)^2=a^2+2ab+b^2[/tex]
[tex](a-b)^2=a^2-2ab+b^2[/tex]
Notice that 25b2 − 45b − 81 and 16x2 − 24x − 9 have too many minus signs. They do not follow the form.
Notice that 49x2 − 28x + 16 would have a=7 and b=4. But 2ab should be 2*4*7=56. This does not follow the form.
Only 9a2 − 30a + 25 follows the form.
