Week 7 in Precalc 11 – Solving Perfect Square Trinomials

This week in Precalculus 11, I learned how to factor Trinomials with perfect squares.

Let’s get started. So first, what is a trinomial with perfect squares?

It is when the first and third numbers are perfect squares (Sometimes the second number may be a perfect square.)

So when we look at this equation, we see that a is a perfect square and 36 is as well. When we are solving these equations, the formula is square root of ax^2 multiplied by the square root of c, then multiplied by 2. This formula ONLY works when you have a perfect square for ax^2 and c.

Here is an example we can try to solve for bx. When we are solving these equations, the formula is square root of ax^2 multiplied by the square root of c, then multiplied by 2.

So we square root both sides, multiply those together then multiply by 2 as seen below.

After we solve bx, we then can factor it.

x^2 + 14x + 49

 

From my previous blog post we know that Product of c, Sum of b. Just by looking, I know that 7×7 is 49 and 7+7 is 14 which matches up with our b value.

So when factored correctly, it should look like this.

(x+7)(x+7)

and we can verify it as well.

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