If a+b equals 4 and ab equals -12 Find
1)a-b
2)a square minus b square
princesarswat:
(a-b) ^2 = (a+b)^2 -4ab = 16- 4(-12) = 16+48= 64. so a-b = 8
by this eqn. we get a= 6 and b = -2 so a^2-b^2 = 36-4 =32
Good trick
hmmmmm
Answers
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a+b=4
ab=-12
a=-12/b
-12/b+b=4
-12+b^2=4b
b^2-4b-12=0
b^2-6b+2b-12=0
b(b-6)+2(b-6)=0
b=6
b=-2
a=-12/6=-2
a=-12/-2=6
a-b=8
a^2-b^2=(a+b) (a-b)
=4*8=32
ab=-12
a=-12/b
-12/b+b=4
-12+b^2=4b
b^2-4b-12=0
b^2-6b+2b-12=0
b(b-6)+2(b-6)=0
b=6
b=-2
a=-12/6=-2
a=-12/-2=6
a-b=8
a^2-b^2=(a+b) (a-b)
=4*8=32
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