find the value of a^2 +b^2: when a-b = 5. and a+b = -9
Naih:
Since, (a+b)^2 = a^2 + b^2 + 2ab Therefore, a^2 + b^2 = (a+b)^2 - 2ab And, Since, (a+b) = -9 Therefore, a^2 + b^2 = 81 -2ab --{1)}. Again, since, (a-b)^2 = a^2+b^2 -2ab Therefore, a^2+b^2 = (a-b)^2 + 2ab = 25+2ab --{2} (since, a-b =5) Now, from eq. {1} &{2}, we get, 81-2ab = 25+ 2ab => 56= 4ab => ab= 14--{3} Put eq. {3} in {1} => a^2+b^2 = 81 - 2(14) = 81-28 => *a^2+b^2= 53*.. Ans..!!
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There's a correction in last 5th line...!! Sorry guys!!
Answers
Answered by
2
a-b=5
a+b=-9
________
+ -
+
2a=-4
a=-4/2
a=-2
b=-7
a^2+b^2= (-2)^2+(-7)^2
=4+49
=53
a+b=-9
________
+ -
+
2a=-4
a=-4/2
a=-2
b=-7
a^2+b^2= (-2)^2+(-7)^2
=4+49
=53
it is the right solution
pretty helpful
:)
make me brainliest
Answered by
3
Hey !!! ^_^
Here is your answer
⬇️⬇️⬇️⬇️⬇️
a + b = -9
a - b = 5
- - -
________
2b = - 14
b = -7
a - b = 5
a - (-7) = 5
a + 7 = 5
a = 12
a² + b²
(a + b)² - 2ab
(9)² - 2 (12) ( -7)
81 + 168
249
Here is your answer
⬇️⬇️⬇️⬇️⬇️
a + b = -9
a - b = 5
- - -
________
2b = - 14
b = -7
a - b = 5
a - (-7) = 5
a + 7 = 5
a = 12
a² + b²
(a + b)² - 2ab
(9)² - 2 (12) ( -7)
81 + 168
249
you are wrong
Hey sister you sure we have to use this formula
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