If a+b=5, and ab=3, what is a^2+b^2?
I'm in 8th grade and im stuck,help?
Answers (2)
You have 2 equations and two unknowns, so you can solve one for a variable and substitute it into the other one.
=> a = 5 - b
Then (5 - b)b = 3
=> -b^2 + 5b - 3 = 0
Now, solve this quadratic equation
You get:
b = (1/2)(5 ± √13)
Now you can use this to find the other variable
=> a = 5 - b
=> a = 5 - (1/2)(5 ± √13)