Evaluate
-15+5i
Real Part
-15
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1\times \left(5i\right)+3\times 5i^{2}
Multiply 1+3i times 5i.
1\times \left(5i\right)+3\times 5\left(-1\right)
By definition, i^{2} is -1.
-15+5i
Do the multiplications. Reorder the terms.
Re(1\times \left(5i\right)+3\times 5i^{2})
Multiply 1+3i times 5i.
Re(1\times \left(5i\right)+3\times 5\left(-1\right))
By definition, i^{2} is -1.
Re(-15+5i)
Do the multiplications in 1\times \left(5i\right)+3\times 5\left(-1\right). Reorder the terms.
-15
The real part of -15+5i is -15.
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