The equation that could represent this situation is 3x + 7 = 40, where x is the length of each of the three equal sides of the quadrilateral.
An algebraic expression is the combination of numbers and variables in expressing and solving a particular mathematical question. An equation is the equality of expressions.
Let x be the length of each of the three equal sides.
If the perimeter of the quadrilateral is 40 inches, and the length of the fourth side is 7 inches, then the sum of the four sides is equal to 40.
x + x + x +7 = 40
3x + 7 = 40
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