9514 1404 393
Answer:
- 58 +106i
- -29 -53i
- -8 -41i
- -15 +19i
Step-by-step explanation:
For the purpose of selecting the appropriate tile, it is only necessary to figure the real part of the sum or product.
We notice that the second product (-xy) is -1/2 times the first product (2xy). This can let you find the answers on that basis alone. The only tiles with a (-1) : (2) relationship are (-29 -53i) : (58 +106i).
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The sum -5x +y has a real part of -5(3) +7 = -8.
The sum 2x -3y has a real part of 2(3) -3(7) = 6 -21 = -15.
Hence the sequence of answers needed on the right side is as shown above.
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Additional comment
You know that arithmetic operations with complex numbers (multiplication and addition) are identical to those operations performed on any polynomials. That is, "i" can be treated as a variable. The simplification comes at the end, where any instances of i² can be replaced by -1.
xy = (3 +8i)(7 -i) = 3·7 -3·i +8·7·i -8·i·i = 21 +53i -8i²
= (21 +8) +53i . . . . replaced i² with -1, so -8i² = +8
= 29 +53i
