Let z1=−3+2i and z2=4−i.
i) z1+z2
Step 1: Add the real parts and the imaginary parts.
z1+z2=(−3+2i)+(4−i)
=(−3+4)+(2−1)i
=1+i
The result is 1+i.
ii) z1−z2
Step 1: Subtract the real parts and the imaginary parts.
z1−z2=(−3+2i)−(4−i)
=−3+2i−4+i
=(−3−4)+(2+1)i
=−7+3i
The result is −7+3i.
iii) z1z2
Step 1: Multiply the complex numbers using the distributive property.
z1z2=(−3+2i)(4−i)
=−3(4)+(−3)(−i)+2i(4)+2i(−i)
=−12+3i+8i−2i2
Step 2: Substitute i2=−1 and simplify.
=−12+11i−2(−1)
=−12+11i+2
=−10+11i
The result is −10+11i.
iv) z2z1
Step 1: Multiply the numerator and denominator by the conjugate of z2.
The conjugate of z2=4−i is 4+i.
z2z1=4−i−3+2i×4+i4+i
Step 2: Expand the numerator.
(−3+2i)(4+i)=−12−3i+8i+2i2
=−12+5i+2(−1)=−14+5i
Step 3: Expand the denominator.
(4−i)(4+i)=42−i2
=16−(−1)=17
Step 4: Combine and express in Cartesian form.
17−14+5i=−1714+175i
The result is −1714+175i.
v) 2z1−5z2
Step 1: Multiply z1 by 2 and z2 by 5.
2z1=2(−3+2i)=−6+4i
5z2=5(4−i)=20−5i
Step 2: Subtract the results.
2z1−5z2=(−6+4i)−(20−5i)
=−6+4i−20+5i
=(−6−20)+(4+5)i
=−26+9i
The result is −26+9i.
vi) −z1−2z2
Step 1: Multiply z1 by −1 and z2 by −2.
−z1=−(−3+2i)=3−2i
−2z2=−2(4−i)=−8+2i
Step 2: Add the results.
−z1−2z2=(3−2i)+(−8+2i)
=(3−8)+(−2+2)i
=−5+0i=−5
The result is −5.
vii) (−z1)(−z2)
Step 1: Multiply −z1 and −z2. This is equivalent to z1z2.
(−z1)(−z2)=(−(−3+2i))(−(4−i))
=(3−2i)(−4+i)
=3(−4)+3(i)−2i(−4)−2i(i)
=−12+3i+8i−2i2
Step 2: Substitute i2=−1 and simplify.
=−12+11i−2(−1)
=−12+11i+2
=−10+11i
The result is −10+11i.
viii) 3z1+2z2
Step 1: Multiply z1 by 3 and z2 by 2.
3z1=3(−3+2i)=−9+6i
2z2=2(4−i)=8−2i
Step 2: Add the results.
3z1+2z2=(−9+6i)+(8−2i)
=(−9+8)+(6−2)i
=−1+4i
The result is −1+4i.
ix) i(z1+z2)
Step 1: Calculate z1+z2.
z1+z2=(−3+2i)+(4−i)=1+i
Step 2: Multiply the sum by i.
i(z1+z2)=i(1+i)
=i(1)+i(i)
=i+i2
Step 3: Substitute i2=−1 and simplify.
=i−1=−1+i
The result is −1+i.
x) z1z2
Step 1: Multiply the numerator and denominator by the conjugate of z1.
The conjugate of z1=−3+2i is −3−2i.
z1z2=−3+2i4−i×−3−2i−3−2i
Step 2: Expand the numerator.
(4−i)(−3−2i)=4(−3)+4(−2i)−i(−3)−i(−2i)
=−12−8i+3i+2i2
=−12−5i+2(−1)=−14−5i
Step 3: Expand the denominator.
(−3+2i)(−3−2i)=(−3)2−(2i)2
=9−4i2
=9−4(−1)=13
Step 4: Combine and express in Cartesian form.
13−14−5i=−1314−135i
The result is −1314−135i.
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