SOLUTION: please help me.......... if(a+b)^2=9 and (a-b)^2=49,what is the value of a^2+b^2

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Question 924875: please help me..........
if(a+b)^2=9 and (a-b)^2=49,what is the value of a^2+b^2
Answer by MathLover1(20850) About Me  (Show Source):
You can put this solution on YOUR website!
%28a%2Bb%29%5E2=9 and %28a-b%29%5E2=49: find a and b
%28a%2Bb%29%5E2=9 ...sqrt of both sides
sqrt%28%28a%2Bb%29%5E2%29=sqrt%289%29
a%2Bb=3 ...solve for a
a=3-b ....eq.1
%28a-b%29%5E2=49
sqrt%28%28a-b%29%5E2%29=sqrt%2849%29
a-b=7 ...solve for a
a=7%2Bb ...eq.2
from eq.1 and eq.2 => 3-b=7%2Bb...solve for b
3-7=b%2Bb
-4=2b
-4%2F2=b
highlight%28b=-2%29
now find a
a=7%2Bb ...eq.2
a=7%2B%28-2%29
a=7-2
highlight%28a=5%29

the value of a%5E2%2Bb%5E2=5%5E2%2B%28-2%29%5E2=25%2B4=29