Evaluate
25+45i
Real Part
25
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5i\times 9+5\left(-5\right)i^{2}
Multiply 5i times 9-5i.
5i\times 9+5\left(-5\right)\left(-1\right)
By definition, i^{2} is -1.
25+45i
Do the multiplications. Reorder the terms.
Re(5i\times 9+5\left(-5\right)i^{2})
Multiply 5i times 9-5i.
Re(5i\times 9+5\left(-5\right)\left(-1\right))
By definition, i^{2} is -1.
Re(25+45i)
Do the multiplications in 5i\times 9+5\left(-5\right)\left(-1\right). Reorder the terms.
25
The real part of 25+45i is 25.
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