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Express the following in the form a+bi ...

Express the following in the form a+bi
`(sqrt3 + 5i) (sqrt3 -5i)^(2) + (-4+ 5i)^(2)`

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To express the given expression \((\sqrt{3} + 5i)(\sqrt{3} - 5i)^2 + (-4 + 5i)^2\) in the form \(a + bi\), we will follow these steps: ### Step 1: Expand \((\sqrt{3} - 5i)^2\) Using the formula for the square of a binomial, \((a - b)^2 = a^2 - 2ab + b^2\): \[ (\sqrt{3} - 5i)^2 = (\sqrt{3})^2 - 2(\sqrt{3})(5i) + (5i)^2 \] Calculating each term: - \((\sqrt{3})^2 = 3\) - \(-2(\sqrt{3})(5i) = -10\sqrt{3}i\) - \((5i)^2 = 25i^2 = 25(-1) = -25\) Combining these, we get: \[ (\sqrt{3} - 5i)^2 = 3 - 10\sqrt{3}i - 25 = -22 - 10\sqrt{3}i \] ### Step 2: Substitute back into the expression Now we substitute this back into the original expression: \[ (\sqrt{3} + 5i)(-22 - 10\sqrt{3}i) + (-4 + 5i)^2 \] ### Step 3: Expand \((\sqrt{3} + 5i)(-22 - 10\sqrt{3}i)\) Using the distributive property: \[ (\sqrt{3} + 5i)(-22 - 10\sqrt{3}i) = \sqrt{3}(-22) + \sqrt{3}(-10\sqrt{3}i) + 5i(-22) + 5i(-10\sqrt{3}i) \] Calculating each term: - \(\sqrt{3}(-22) = -22\sqrt{3}\) - \(\sqrt{3}(-10\sqrt{3}i) = -30i\) - \(5i(-22) = -110i\) - \(5i(-10\sqrt{3}i) = -50(-1) = 50\) Combining these, we get: \[ -22\sqrt{3} + 50 - (30 + 110)i = 50 - 22\sqrt{3} - 140i \] ### Step 4: Expand \((-4 + 5i)^2\) Using the formula for the square of a binomial: \[ (-4 + 5i)^2 = (-4)^2 + 2(-4)(5i) + (5i)^2 \] Calculating each term: - \((-4)^2 = 16\) - \(2(-4)(5i) = -40i\) - \((5i)^2 = 25i^2 = -25\) Combining these, we have: \[ (-4 + 5i)^2 = 16 - 40i - 25 = -9 - 40i \] ### Step 5: Combine all parts Now we combine the results from Steps 3 and 4: \[ (50 - 22\sqrt{3} - 140i) + (-9 - 40i) \] Combining like terms: - Real part: \(50 - 9 - 22\sqrt{3} = 41 - 22\sqrt{3}\) - Imaginary part: \(-140 - 40 = -180\) Thus, we have: \[ 41 - 22\sqrt{3} - 180i \] ### Final Result The expression in the form \(a + bi\) is: \[ \boxed{(41 - 22\sqrt{3}) - 180i} \]
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ICSE-COMPLEX NUMBERS-Chapter Test
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  4. Express (13i)/(2-3i) in the form A + Bi

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  13. Find the locus of a complex number z= x + yi, satisfying the relation ...

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  19. Find the value of x and y given that (x + yi) (2-3i)=4+i

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  20. If the ratio (z-i)/(z-1) is purely imaginary, prove that the point z l...

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  21. If (-2 + sqrt-3) (-3 + 2 sqrt-3) = a + bi, find the real numbers a and...

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