Find the Excluded Values (3x)/(x^2+3x-28)-(2x)/(x^2+x-20)

$\frac{3 x}{x^{2} + 3 x - 28} - \frac{2 x}{x^{2} + x - 20}$

Step 1

Set the denominator in $\frac{3 x}{x^{2} + 3 x - 28}$ equal to $0$ to find where the expression is undefined.

$x^{2} + 3 x - 28 = 0$

Step 2

Solve for $x$ .

Factor $x^{2} + 3 x - 28$ using the AC method.

Consider the form $x^{2} + b x + c$ . Find a pair of integers whose product is $c$ and whose sum is $b$ . In this case, whose product is $- 28$ and whose sum is $3$ .

$- 4, 7$

Write the factored form using these integers.

$(x - 4) (x + 7) = 0$

If any individual factor on the left side of the equation is equal to $0$ , the entire expression will be equal to $0$ .

$x - 4 = 0$

$x + 7 = 0$

Set $x - 4$ equal to $0$ and solve for $x$ .

Set $x - 4$ equal to $0$ .

$x - 4 = 0$

Add $4$ to both sides of the equation.

$x = 4$

Set $x + 7$ equal to $0$ and solve for $x$ .

Set $x + 7$ equal to $0$ .

$x + 7 = 0$

Subtract $7$ from both sides of the equation.

$x = - 7$

The final solution is all the values that make $(x - 4) (x + 7) = 0$ true.

$x = 4, - 7$

Step 3

Set the denominator in $\frac{2 x}{x^{2} + x - 20}$ equal to $0$ to find where the expression is undefined.

$x^{2} + x - 20 = 0$

Step 4

Solve for $x$ .

Factor $x^{2} + x - 20$ using the AC method.

Consider the form $x^{2} + b x + c$ . Find a pair of integers whose product is $c$ and whose sum is $b$ . In this case, whose product is $- 20$ and whose sum is $1$ .

$- 4, 5$

Write the factored form using these integers.

$(x - 4) (x + 5) = 0$

If any individual factor on the left side of the equation is equal to $0$ , the entire expression will be equal to $0$ .

$x - 4 = 0$

$x + 5 = 0$

Set $x - 4$ equal to $0$ and solve for $x$ .

Set $x - 4$ equal to $0$ .

$x - 4 = 0$

Add $4$ to both sides of the equation.

$x = 4$

Set $x + 5$ equal to $0$ and solve for $x$ .

Set $x + 5$ equal to $0$ .

$x + 5 = 0$

Subtract $5$ from both sides of the equation.

$x = - 5$

The final solution is all the values that make $(x - 4) (x + 5) = 0$ true.

$x = 4, - 5$

Step 5

The equation is undefined where the denominator equals $0$ , the argument of a square root is less than $0$ , or the argument of a logarithm is less than or equal to $0$ .

$x = - 7, x = - 5, x = 4$

Step 6

Find the Excluded Values (3x)/(x^2+3x-28)-(2x)/(x^2+x-20)

Related Questions

Support LCMGCF.com by disabling your adblocker.