Complete the Square: Fill in the Blanks for (x+?)^2 = x^2 + ? + 25

Question

Fill in the blanks:

(x+?)2=x2+?+25 (x+?)^2=x^2+?+25

Video Solution

Solution Steps

00:00 Complete the missing
00:03 Let's mark the unknown with A
00:11 Let's use the shortened multiplication formulas to open the parentheses
00:19 Let's compare the coefficients and solve for A
00:31 Let's substitute and solve
00:42 And this is the solution to the question

Step-by-Step Solution

To solve this problem, we'll use the formula for the square of a sum, (a+b)2=a2+2ab+b2(a+b)^2 = a^2 + 2ab + b^2. This will help us determine the missing components in the expression.

The expression given is (x+?)2=x2+?+25(x+?)^2 = x^2 + ? + 25.

First, match it to the expanded form:

(x+b)2=x2+2bx+b2(x+b)^2 = x^2 + 2bx + b^2.

According to the problem, the expanded form is x2+?+25x^2 + ? + 25. This means b2=25b^2 = 25, so:
b2=25 b^2 = 25
Therefore, b=5b = 5 or b=5b = -5. For simplicity, let's choose b=5b = 5.

Now, calculate 2bx2bx:
2bx=2×5×x=10x 2bx = 2 \times 5 \times x = 10x

Substituting bb into the equation, we have:

(x+5)2=x2+10x+25(x+5)^2 = x^2 + 10x + 25.

Thus, the missing numbers are 55 and 10x10x.

Therefore, the solution to the problem is 5,10x 5, 10x .

Answer

5,10x 5,10x