Evaluate
-25i
Real Part
0
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3\times 4+3\times \left(-3i\right)-4i\times 4-4\left(-3\right)i^{2}
Multiply complex numbers 3-4i and 4-3i like you multiply binomials.
3\times 4+3\times \left(-3i\right)-4i\times 4-4\left(-3\right)\left(-1\right)
By definition, i^{2} is -1.
12-9i-16i-12
Do the multiplications.
12-12+\left(-9-16\right)i
Combine the real and imaginary parts.
-25i
Do the additions.
Re(3\times 4+3\times \left(-3i\right)-4i\times 4-4\left(-3\right)i^{2})
Multiply complex numbers 3-4i and 4-3i like you multiply binomials.
Re(3\times 4+3\times \left(-3i\right)-4i\times 4-4\left(-3\right)\left(-1\right))
By definition, i^{2} is -1.
Re(12-9i-16i-12)
Do the multiplications in 3\times 4+3\times \left(-3i\right)-4i\times 4-4\left(-3\right)\left(-1\right).
Re(12-12+\left(-9-16\right)i)
Combine the real and imaginary parts in 12-9i-16i-12.
Re(-25i)
Do the additions in 12-12+\left(-9-16\right)i.
0
The real part of -25i is 0.
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