Mistake in expression

While attempting to multiply the expression (2 - 5i)(5 + 2i) a student made a mistake.

(2 - 5i)(5 + 2i) = 10 + 4i - 25i - 10i2
= 10 + 4(-1) - 25(-1) - 10(1)
= 10 - 4 + 25 - 10
= 21

Complete the explanation and correct the error.

Hint: The student incorrectly defined i as being equal to ___ instead of ___. The student should have written the product as :

Result

x = (Correct answer is: 20-21i) Wrong answer

Step-by-step explanation:

x=(25i) (5+2i) x=2 5+2 2i+(5i) 5+(5i) 2i x=10+4i25i10i2 x=10+4i25i+10 x=10+10+i(425)  x=2021i



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