maci56153 maci56153 09-05-2024 Mathematics contestada 7. The perimeter of the shown triangle is 21 cm. Find the lengths of its sides. 7x-5 7 -3(x-1) M.4 cm | P. 6 cm ] R. 8 cm | S. 9 cm ☐ T. 11 cm 14 - 3x