Final answer:
The length of the base of the isosceles triangle is 19 cm.
Step-by-step explanation:
To find the length of the base of the isosceles triangle, we need to use the fact that the perimeter of a triangle is the sum of the lengths of its sides. The perimeter formula for this triangle is (2x - 5) + (x + 7) + (x + 7) = 50. Simplifying the equation, we get 4x + 9 = 50. Solving for x, we find x = 10. Substituting the value of x back into the expression for the length of the base, the length of the base is (10 + 7) cm = 17 cm. Therefore, the correct option is (B) 19 cm.
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