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Solve the equation by completing the square. Round to the nearest hundredth if necessary. x2 + 3x – 5 = 0

2 Answers

1 vote
The answer is x = 1.19 and x = -4.19
User Sotti
by
5.8k points
7 votes

Answer: The required solution is


x=1.19,~-4.19.

Step-by-step explanation: We are given to solve the following quadratic equation by the method of completing the square :


x^2+3x-5=0.

We have


x^2+3x-5=0\\\\\Rightarrow x^2+3x=5\\\\\Rightarrow x^2+2* x* (3)/(2)+\left((3)/(2)\right)^2=5+\left((3)/(2)\right)^2\\\\\\\Rightarrow \left(x+(3)/(2)\right)^2=5+(9)/(4)\\\\\\\Rightarrow x+(3)/(2)=\pm(√(29))/(2)\\\\\\\Rightarrow x=-(3)/(2)\pm(√(29))/(2)\\\\\\\Rightarrow x=(-3\pm√(29))/(2)\\\\\Rightarrow x=(-3\pm5.38)/(2)\\\\\\\Rightarrow x=(2.38)/(2),~~(-8.38)/(2)\\\\\\\Rightarrow x=1.19,~-4.19

Thus, the required solution is


x=1.19,~-4.19.

User Richard West
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6.7k points