If [tex]$x = -3$[/tex] is a solution to [tex]$x^2 + 7x + 12 = 0$[/tex], which of the following could also be the value of [tex][tex]$x$[/tex][/tex]?

A. -5
B. -4
C. 1
D. 2
E. 3



Answer :

To determine the other solution to the quadratic equation [tex]\(x^2 + 7x + 12 = 0\)[/tex] given that [tex]\(x = -3\)[/tex] is one of the solutions, we can follow these steps:

1. Understand the structure of the quadratic equation:
A quadratic equation of the form [tex]\(ax^2 + bx + c = 0\)[/tex] typically has two solutions. These solutions can be found using factoring or the quadratic formula. Here, our equation is [tex]\(x^2 + 7x + 12 = 0\)[/tex].

2. Recall that [tex]\(x = -3\)[/tex] is a solution:
Since [tex]\(x = -3\)[/tex] is given as one solution, we recognize that [tex]\(-3\)[/tex] satisfies the equation. This means when we substitute [tex]\(-3\)[/tex] back into the equation, it should equal zero.

3. Factor the quadratic equation:
We can factor [tex]\(x^2 + 7x + 12 = 0\)[/tex] to find its roots. The factors of the quadratic equation are typically in the form [tex]\((x - p)(x - q) = 0\)[/tex] where [tex]\(p\)[/tex] and [tex]\(q\)[/tex] are the solutions.

[tex]\[ x^2 + 7x + 12 = (x + 3)(x + 4) \][/tex]

4. Verify the factored form:
By expanding [tex]\((x + 3)(x + 4)\)[/tex], we get:

[tex]\[ (x + 3)(x + 4) = x^2 + 4x + 3x + 12 = x^2 + 7x + 12 \][/tex]

This confirms that the factors are correct.

5. Determine the solutions from the factored form:
Setting each factor equal to zero gives the solutions:

[tex]\[ x + 3 = 0 \quad \text{or} \quad x + 4 = 0 \][/tex]
Solving these equations, we get:

[tex]\[ x = -3 \quad \text{or} \quad x = -4 \][/tex]

6. Identify the correct solution from the options:
The given options are:
- (A) -5
- (B) -4
- (C) 1
- (D) 2
- (E) 3

From our factored results, we see that [tex]\(x = -4\)[/tex] is the other solution besides [tex]\(x = -3\)[/tex].

Therefore, the other value of [tex]\( x \)[/tex] is [tex]\(\boxed{-4}\)[/tex].

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