Answer:
(a+b)^2+(a-b)^2=2(a^2+b^2)
expanding:
a² + 2ab + b² + a² -2ab + b² = 2a² + 2b²
2a² + 2b² = 2a² + 2b²
60
Step-by-step explanation:
15x3=45
5x3=15
15+45=60
