The choices that i get are a) 121 b) 121/4 c) -11/2 d) 121/2

I've tried everyone of them and they don't make any sense.

The choices that i get are a) 121 b) 121/4 c) -11/2 d) 121/2

I've tried everyone of them and they don't make any sense.

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Hi Brittani,

We know that a perfect square trinomial must either look like * a^{2 }+ 2ab + b^{2}* or

The key is to set -11x equal to -2ab since they are both the middle term of the trinomial.

**-11x = -2ab**

In your example, a must equal x, since x is the square root of the first term. Substitute into the equation.

**-11x = -2(x)b
**Next, divide both sides by -2x in order to isolate b. Simplify by cancelling the negatives and the x's.

The last term of the trinomial is equal to b^{2}, so you will have to square both sides of the previous equation.

**b ^{2}=(11/2)^{2}=121/4**

So the last term of the trinomial must be 121/4 (choice B).

Good Luck,

Shawn

Completing the square,

x² – 11x + c = [x - (11/2)]^2 = x^2 - 11x + 121/4

Therefore, c = (11/2)^2 = 121/4

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