PROBLEM.... math problem!?

Question

 

How do I solve a^2+b^2= if a+b=4 a*b=3 ... please help me.. I want to pass the exams and this is from my homework and I`ve searched but I didn`t find anything ... I forgot how to solve those..

Answer 1

a²+b² = ?

a²+b² = (a+b)² -2ab

a²+b² = (4)² - 2(3)      (a+b=4 and a×b =3)

a²+b² =16 -6               ((4)² = 4×4 = 16; 2×3 =6)

a²+b² =10                    ( 16 -6 = 10)

The solution is   a²+b² =10