if (1+2i) (3-4i) = x+iy , show that x^2+y^2=125
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(1+2i)(3-4i)
(3-4i+6i-8i^2) i^2=-1
(3+8+2i)
(11+2i)
compare with x+iy
u get x =11 y=2
x^2 = 121. y^2= 4
therefore x^2 +y^2 = 121+4=125.
(3-4i+6i-8i^2) i^2=-1
(3+8+2i)
(11+2i)
compare with x+iy
u get x =11 y=2
x^2 = 121. y^2= 4
therefore x^2 +y^2 = 121+4=125.
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