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Determine the number that will complete the square to solve the equation after the constant term has been written on the right side. Do not solve the equation.

x2+3x−18=0

User Yixing Lao
by
5.2k points

2 Answers

3 votes

Answer:

2.25.

Explanation:

x^2 + 3x - 18 = 0

First, we need to write the constant on the right of the equation. So, we add 18 to both sides.

x^2 + 3x = 18.

Now, we find the number that will complete the square. It will be
((b)/(2) )^2.

In this case, b = 3.


((3)/(2) )^2

= (1.5)^2

= 2.25.

So, the number that will complete the square to solve the equation is 2.25, or 2 and 1/4, or 9/4.

Hope this helps!

User Eresonance
by
4.3k points
2 votes

Answer:

Explanation:

Hello, "the constant term has been written on the right side", it means that we add 18 to both sides to get.


x^2+3x-18=0\\\\x^2+3x=18\\\\\text{We can see the beginning of } (x+(3)/(2))^2 \\\\x^2+3x=(x+(3)/(2))^2-(3^3)/(2^2)=18\\\\(x+(3)/(2))^2=18+(9)/(4)=(18*4+9)/(4)=(81)/(4)

Hope this helps.

Thank you.

User Juan Marco
by
5.1k points