Shayna enlarged a square photo by adding 10 inches to each side so it could be seen on a large poster. The area of the enlarged photo is 256 square inches. In the equation [tex]\((x+10)^2=256\)[/tex], [tex]\(x\)[/tex] represents the side measure of the original square photo.

What were the dimensions of the original photo?

A. 4 inches by 4 inches
B. 6 inches by 6 inches
C. 10 inches by 10 inches
D. 12 inches by 12 inches



Answer :

To solve the problem of finding the dimensions of the original square photo, we start with the equation given:

[tex]$(x + 10)^2 = 256$[/tex]

Here, [tex]\( x \)[/tex] represents the side measure of the original square photo, and the equation describes the relationship between the side length of the original photo and the enlarged photo.

Step-by-Step Breakdown:

1. Understand the equation:
The equation [tex]\((x + 10)^2 = 256\)[/tex] suggests that if you add 10 inches to each side of the original square photo, the area of the enlarged photo becomes 256 square inches.

2. Solve for [tex]\( x + 10 \)[/tex]:
To isolate [tex]\( x \)[/tex], we first take the square root of both sides of the equation:
[tex]\[ \sqrt{(x + 10)^2} = \sqrt{256} \][/tex]
This simplifies to:
[tex]\[ x + 10 = 16 \quad \text{or} \quad x + 10 = -16 \][/tex]

3. Determine valid solution:
Since [tex]\( x \)[/tex] represents a physical length (the side of a square), we discard the negative solution as length cannot be negative. Therefore:
[tex]\[ x + 10 = 16 \][/tex]

4. Solve for [tex]\( x \)[/tex]:
Subtract 10 from both sides to find [tex]\( x \)[/tex]:
[tex]\[ x = 16 - 10 \][/tex]
Which gives us:
[tex]\[ x = 6 \][/tex]

5. Verify the solution:
The original side length [tex]\( x \)[/tex] is therefore 6 inches. To confirm this, we can check our work:
[tex]\[ (6 + 10)^2 = 16^2 = 256 \][/tex]
Which is correct, since the area of the enlarged photo indeed turns out to be 256 square inches.

Conclusion:
The dimensions of the original square photo were [tex]\(6\)[/tex] inches by [tex]\(6\)[/tex] inches. Therefore, the correct answer is:

6 inches by 6 inches.