If 2l - 3m = -1 and lm = 20, then the value of
4l^2 + 9m^2 is
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Answered by
2
4l^2+9m^2=241
answer is 241
answer is 241
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naveenbrainly:
how 12lm came
please say
2l-3m)^2=4l^2+9m^2-2*2l*3m
ok but how -12lm came
how minus came for the 12
2*2L*3m=12Lm
(a-b)^2 =a^2+b^2-2ab
Answered by
2
2l - 3m = -1
(2l - 3m)^2 = -1^2
(2l)^2 + (3m)^2 - 2× 2l × 3m = 1
4l^2 + 9m^2 - 12lm = 1
4l^2 + 9m^2 - 12×20 = 1
4l^2 + 9m^2 = 240+1
4l^2 + 9m^2 = 241
(2l - 3m)^2 = -1^2
(2l)^2 + (3m)^2 - 2× 2l × 3m = 1
4l^2 + 9m^2 - 12lm = 1
4l^2 + 9m^2 - 12×20 = 1
4l^2 + 9m^2 = 240+1
4l^2 + 9m^2 = 241
how 12lm came
see now
it is (a-b)^2 formula....understood?
see the answer now
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