$\left \{ {{y+4x=12} \atop {3y=8-12x}} \right. \\\\ \left \{ {{y=12-4x} \atop {3y=8-12x}} \right. \\\\3(12-4x)=8-12x\\\\36-12x=8-12x\\\\-12x+12x=8-36\\\\0\neq28\\\\There\ are\ no\ solutions.$

6 0

4 years ago

An arithmetic sequence has this recursive formula:

horsena [70]

Answer:

$\text{\bf{C.}}\quad a_n=4+(n-1)(-7)$

Step-by-step explanation:

An arithmetic sequence that is described by the explicit formula ...

$a_n=a_1+(n-1)d$

can also be described by the recursive formula ...

$\left \{\begin{array}{l}a_1=\text{(first term)}&a_n=a_{n-1}+d&\end{array}\right.$

Matching parts of the formulas, we see that a1 = 4, d = -7. Putting these values into the explicit formula gives ...

$a_n=4+(n-1)(-7)$

4 0

3 years ago

(2n – 3)(5n+6)<br> How do I solve this ?

nalin [4]

Answer:

Step-by-step explanation:

(2n - 3)(5n + 6) = 2n*(5n + 6) -3*(5n +6)

=2n*5n + 2n*6 -3*5n + (-3)*6

=10n² + 12n - 15n - 18

= 10n² -3n - 18

5 0

3 years ago

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