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

Express the following in the form a+bi
`(8+7i) (8-7i)`

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To express the product \((8 + 7i)(8 - 7i)\) in the form \(a + bi\), we can follow these steps: ### Step 1: Identify the expression We start with the expression: \[ (8 + 7i)(8 - 7i) \] ### Step 2: Recognize the formula This expression can be recognized as a difference of squares, which follows the formula: \[ (x + y)(x - y) = x^2 - y^2 \] Here, we can let \(x = 8\) and \(y = 7i\). ### Step 3: Apply the formula Using the formula, we can rewrite the expression: \[ (8 + 7i)(8 - 7i) = 8^2 - (7i)^2 \] ### Step 4: Calculate \(8^2\) Now we calculate \(8^2\): \[ 8^2 = 64 \] ### Step 5: Calculate \((7i)^2\) Next, we calculate \((7i)^2\): \[ (7i)^2 = 7^2 \cdot i^2 = 49 \cdot i^2 \] Since \(i^2 = -1\), we have: \[ (7i)^2 = 49 \cdot (-1) = -49 \] ### Step 6: Substitute back into the expression Now we substitute back into the expression: \[ 8^2 - (7i)^2 = 64 - (-49) = 64 + 49 \] ### Step 7: Simplify the expression Now we simplify: \[ 64 + 49 = 113 \] ### Step 8: Write in the form \(a + bi\) Since there is no imaginary part, we can express this as: \[ 113 + 0i \] ### Conclusion Thus, the expression \((8 + 7i)(8 - 7i)\) in the form \(a + bi\) is: \[ \boxed{113 + 0i} \]
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ICSE-COMPLEX NUMBERS-Chapter Test
  1. Express the following in the form a+bi (8+7i) (8-7i)

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  2. Find the square root of 5-12i

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

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  4. Express (13i)/(2-3i) in the form A + Bi

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  5. If z= x +yi and (|z-1-i|+4)/(3|z-1-i|-2)=1, show that x^(2) + y^(2) -2...

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  6. If omega and omega^(2) are cube roots of unity, prove that (2- omega +...

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  7. If z(1), z(2) in C (set of complex numbers), prove that |z(1) + z(2)| ...

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  8. If z = x + yi, omega = (2-iz)/(2z-i) and |omega|=1, find the locus of ...

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  9. Simplify: (1- 3omega + omega^(2)) (1 + omega- 3omega^(2))

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  10. Find the locus of z satisfying |(z-3)/(z+1)|=3 in the complex plane.

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  11. Given that (2 sqrt3 cos 30^(@) - 2i sin 30^(@))/(sqrt2 (cos 45^(@) + i...

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  12. Simplify : (1- omega) (1- omega^(2)) (1- omega^(4)) (1- omega^(8))

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

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  14. Find the real values of x and y satisfying the equality (x-2 + (y-3)i)...

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  15. If i= (sqrt-1), prove that following (x+1+i) (x+ 1-i) (x-1-i) (x-1+ i)...

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  16. If z= x + yi and |2z + 1| = |z- 2i|, show that 3(x^(2) + y^(2)) + 4(x-...

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  17. Find the amplitude of the complex number "sin" (6pi)/(5) + i (1- "cos"...

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  18. Express (1- 2i)/(2+i) + (3+i)/(2-i) in the form a + bi

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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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