Question

2. The two equal sides of an isosceles triangle each have a length of 4x + y - 5. The perimeter of the triangle is

10x + 4y - 18. Determine the length of the third side. Explain how you found your answer. (4 marks)

Answer 1

9514 1404 393

Answer:

2x +2y -8

Explanation:

If the equal sides are 'a' and the third side is 'b', then the perimeter is ...

P = a +a +b = 2a +b

The length of the third side is then ...

b = P -2a . . . . . . subtract 2a from both sides

Substituting the given expressions, we find ...

b = (10x +4y -18) -2(4x +y -5)

b = 10x +4y -18 -8x -2y +10

b = 2x +2y -8 . . . . the length of the third side