X over 2 space minus space 12 space equals space 20

5(-9w) put expression in distributive property

Offering 30 if a plus b plus c equals 68 and ab plus bc plus ca equals 1121, where a, b, and c are all prime numbers, find the value of abc. the answer is 1978 but i need an explanation on how to get that.

How do the definitions, properties, and postulates you've learned about line segments, parallel lines, and angles to define the shapes of polygons