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1 vote
How do you rewrite an equation by completing the square?
x^2+10x+21=0

User Zinga
by
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1 Answer

5 votes

Answer:

Explanation:

x²+10x+21=0

x²+10x+(10/2)²-(10/2)²+21=0

x²+10x+25-25+21=0

(x+5)²-4=0

(x+5)²=4

(x+y)²=(x+y)(x+y)=x(x+y)+y(x+y)=x²+xy+xy+y²=x²+2xy+y²

(x+y)²=x²+2xy+y²

coefficient of x=2y

y²=[(coefficient of x)/2]²=(2y/2)²=y²

User BastienSander
by
6.7k points
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