1. The problem gives four quadratic equations and partly factored forms with one missing factor in each. We will complete the factoring and then find the two values of $x$ for each.
2. For $x^2 + 6x + 8 = 0$, the given factor is $(x + 2)$. To find the missing factor, divide the quadratic by $(x + 2)$ or find the other root:
The roots multiply to $8$ and add to $6$. Since $2$ is a root (from $x+2=0$), the other root is $4$ because $2 \times 4 = 8$ and $2 + 4 = 6$.
So, missing factor is $(x + 4)$.
Solutions:
$$x = -2 \text{ or } x = -4$$
3. For $x^2 - 4x + 3 = 0$ with factor $(x - 3)$ given, the roots must multiply to $3$ and sum to $4$ (since coefficient of $x$ is $-4$ and factoring signs show roots are positive). One root is $3$, so the other root is $1$.
Missing factor:
$$(x - 1)$$
Solutions:
$$x = 3 \text{ or } x = 1$$
4. For $x^2 + 4x - 21 = 0$, given factor is $(x - 3)$. Roots multiply to $-21$ and add to $4$.
Since $3$ is a root, the other root $r$ satisfies $3 \times r = -21$, so $r = -7$.
Missing factor:
$$(x + 7)$$
Solutions:
$$x = 3 \text{ or } x = -7$$
5. For $x^2 - 8x - 9 = 0$, given factor is $(x + 1)$. Roots multiply to $-9$ and add to $8$ (opposite sign from middle term).
Since root $-1$ from $(x + 1)$ is known, the other root $r$ satisfies $(-1) \times r = -9$, so $r = 9$.
Missing factor:
$$(x - 9)$$
Solutions:
$$x = -1 \text{ or } x = 9$$
Factor And Solve
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