Find the Center and Radius x^2+y^2-3x-4y+4=0

$x^{2} + y^{2} - 3 x - 4 y + 4 = 0$

Step 1

Subtract $4$ from both sides of the equation.

$x^{2} + y^{2} - 3 x - 4 y = - 4$

Step 2

Complete the square for $x^{2} - 3 x$ .

Use the form $a x^{2} + b x + c$ , to find the values of $a$ , $b$ , and $c$ .

$a = 1$

$b = - 3$

$c = 0$

Consider the vertex form of a parabola.

$a {(x + d)}^{2} + e$

Find the value of $d$ using the formula $d = \frac{b}{2 a}$ .

Substitute the values of $a$ and $b$ into the formula $d = \frac{b}{2 a}$ .

$d = \frac{- 3}{2 \cdot 1}$

Simplify the right side.

Multiply $2$ by $1$ .

$d = \frac{- 3}{2}$

Move the negative in front of the fraction.

$d = - \frac{3}{2}$

Find the value of $e$ using the formula $e = c - \frac{b^{2}}{4 a}$ .

Substitute the values of $c$ , $b$ and $a$ into the formula $e = c - \frac{b^{2}}{4 a}$ .

$e = 0 - \frac{{(- 3)}^{2}}{4 \cdot 1}$

Simplify the right side.

Simplify each term.

Raise $- 3$ to the power of $2$ .

$e = 0 - \frac{9}{4 \cdot 1}$

Multiply $4$ by $1$ .

$e = 0 - \frac{9}{4}$

Subtract $\frac{9}{4}$ from $0$ .

$e = - \frac{9}{4}$

Substitute the values of $a$ , $d$ , and $e$ into the vertex form ${(x - \frac{3}{2})}^{2} - \frac{9}{4}$ .

${(x - \frac{3}{2})}^{2} - \frac{9}{4}$

Step 3

Substitute ${(x - \frac{3}{2})}^{2} - \frac{9}{4}$ for $x^{2} - 3 x$ in the equation $x^{2} + y^{2} - 3 x - 4 y = - 4$ .

${(x - \frac{3}{2})}^{2} - \frac{9}{4} + y^{2} - 4 y = - 4$

Step 4

Move $- \frac{9}{4}$ to the right side of the equation by adding $\frac{9}{4}$ to both sides.

${(x - \frac{3}{2})}^{2} + y^{2} - 4 y = - 4 + \frac{9}{4}$

Step 5

Complete the square for $y^{2} - 4 y$ .

Use the form $a x^{2} + b x + c$ , to find the values of $a$ , $b$ , and $c$ .

$a = 1$

$b = - 4$

$c = 0$

Consider the vertex form of a parabola.

$a {(x + d)}^{2} + e$

Find the value of $d$ using the formula $d = \frac{b}{2 a}$ .

Substitute the values of $a$ and $b$ into the formula $d = \frac{b}{2 a}$ .

$d = \frac{- 4}{2 \cdot 1}$

Cancel the common factor of $- 4$ and $2$ .

Factor $2$ out of $- 4$ .

$d = \frac{2 \cdot - 2}{2 \cdot 1}$

Cancel the common factors.

Factor $2$ out of $2 \cdot 1$ .

$d = \frac{2 \cdot - 2}{2 (1)}$

Cancel the common factor.

$d = \frac{2 \cdot - 2}{2 \cdot 1}$

Rewrite the expression.

$d = \frac{- 2}{1}$

Divide $- 2$ by $1$ .

$d = - 2$

Find the value of $e$ using the formula $e = c - \frac{b^{2}}{4 a}$ .

Substitute the values of $c$ , $b$ and $a$ into the formula $e = c - \frac{b^{2}}{4 a}$ .

$e = 0 - \frac{{(- 4)}^{2}}{4 \cdot 1}$

Simplify the right side.

Simplify each term.

Cancel the common factor of ${(- 4)}^{2}$ and $4$ .

Rewrite $- 4$ as $- 1 (4)$ .

$e = 0 - \frac{{(- 1 (4))}^{2}}{4 \cdot 1}$

Apply the product rule to $- 1 (4)$ .

$e = 0 - \frac{{(- 1)}^{2} \cdot 4^{2}}{4 \cdot 1}$

Raise $- 1$ to the power of $2$ .

$e = 0 - \frac{1 \cdot 4^{2}}{4 \cdot 1}$

Multiply $4^{2}$ by $1$ .

$e = 0 - \frac{4^{2}}{4 \cdot 1}$

Factor $4$ out of $4^{2}$ .

$e = 0 - \frac{4 \cdot 4}{4 \cdot 1}$

Cancel the common factors.

Factor $4$ out of $4 \cdot 1$ .

$e = 0 - \frac{4 \cdot 4}{4 (1)}$

Cancel the common factor.

$e = 0 - \frac{4 \cdot 4}{4 \cdot 1}$

Rewrite the expression.

$e = 0 - \frac{4}{1}$

Divide $4$ by $1$ .

$e = 0 - 1 \cdot 4$

Multiply $- 1$ by $4$ .

$e = 0 - 4$

Subtract $4$ from $0$ .

$e = - 4$

Substitute the values of $a$ , $d$ , and $e$ into the vertex form ${(y - 2)}^{2} - 4$ .

${(y - 2)}^{2} - 4$

Step 6

Substitute ${(y - 2)}^{2} - 4$ for $y^{2} - 4 y$ in the equation $x^{2} + y^{2} - 3 x - 4 y = - 4$ .

${(x - \frac{3}{2})}^{2} + {(y - 2)}^{2} - 4 = - 4 + \frac{9}{4}$

Step 7

Move $- 4$ to the right side of the equation by adding $4$ to both sides.

${(x - \frac{3}{2})}^{2} + {(y - 2)}^{2} = - 4 + \frac{9}{4} + 4$

Step 8

Simplify $- 4 + \frac{9}{4} + 4$ .

Find the common denominator.

Write $- 4$ as a fraction with denominator $1$ .

${(x - \frac{3}{2})}^{2} + {(y - 2)}^{2} = \frac{- 4}{1} + \frac{9}{4} + 4$

Multiply $\frac{- 4}{1}$ by $\frac{4}{4}$ .

${(x - \frac{3}{2})}^{2} + {(y - 2)}^{2} = \frac{- 4}{1} \cdot \frac{4}{4} + \frac{9}{4} + 4$

Multiply $\frac{- 4}{1}$ by $\frac{4}{4}$ .

${(x - \frac{3}{2})}^{2} + {(y - 2)}^{2} = \frac{- 4 \cdot 4}{4} + \frac{9}{4} + 4$

Write $4$ as a fraction with denominator $1$ .

${(x - \frac{3}{2})}^{2} + {(y - 2)}^{2} = \frac{- 4 \cdot 4}{4} + \frac{9}{4} + \frac{4}{1}$

Multiply $\frac{4}{1}$ by $\frac{4}{4}$ .

${(x - \frac{3}{2})}^{2} + {(y - 2)}^{2} = \frac{- 4 \cdot 4}{4} + \frac{9}{4} + \frac{4}{1} \cdot \frac{4}{4}$

Multiply $\frac{4}{1}$ by $\frac{4}{4}$ .

${(x - \frac{3}{2})}^{2} + {(y - 2)}^{2} = \frac{- 4 \cdot 4}{4} + \frac{9}{4} + \frac{4 \cdot 4}{4}$

Combine the numerators over the common denominator.

${(x - \frac{3}{2})}^{2} + {(y - 2)}^{2} = \frac{- 4 \cdot 4 + 9 + 4 \cdot 4}{4}$

Simplify each term.

Multiply $- 4$ by $4$ .

${(x - \frac{3}{2})}^{2} + {(y - 2)}^{2} = \frac{- 16 + 9 + 4 \cdot 4}{4}$

Multiply $4$ by $4$ .

${(x - \frac{3}{2})}^{2} + {(y - 2)}^{2} = \frac{- 16 + 9 + 16}{4}$

Simplify by adding numbers.

Add $- 16$ and $9$ .

${(x - \frac{3}{2})}^{2} + {(y - 2)}^{2} = \frac{- 7 + 16}{4}$

Add $- 7$ and $16$ .

${(x - \frac{3}{2})}^{2} + {(y - 2)}^{2} = \frac{9}{4}$

Step 9

This is the form of a circle. Use this form to determine the center and radius of the circle.

${(x - h)}^{2} + {(y - k)}^{2} = r^{2}$

Step 10

Match the values in this circle to those of the standard form. The variable $r$ represents the radius of the circle, $h$ represents the x-offset from the origin, and $k$ represents the y-offset from origin.

$r = \frac{3}{2}$

$h = \frac{3}{2}$

$k = 2$

Step 11

The center of the circle is found at $(h, k)$ .

Center: $(\frac{3}{2}, 2)$

Step 12

These values represent the important values for graphing and analyzing a circle.

Center: $(\frac{3}{2}, 2)$

Radius: $\frac{3}{2}$

Step 13

Find the Center and Radius x^2+y^2-3x-4y+4=0

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