Final answer:
The value of x that makes the perimeters of the two designs equal is x = -2.
Step-by-step explanation:
The perimeters of the two designs can be found by simplifying the expressions:
Design 1: 3x + 7
Design 2: x + 3
To find the value of x for which the perimeters are equal, we set the two expressions equal to each other:
3x + 7 = x + 3
By solving this equation for x, we can find the value that makes the perimeters equal.
Step 1: Subtract x from both sides:
2x + 7 = 3
Step 2: Subtract 7 from both sides:
2x = -4
Step 3: Divide both sides by 2:
x = -2
Therefore, the value of x that makes the perimeters of the two designs equal is x = -2.