Hello darklight

Welcome to Math Help Forum! Originally Posted by

**darklight** Only two simple questions

(REally i am not good at math and i am in the 10th grade)

This is my first post and hope to get some little help .In the summer i have tryed hacking now math has replaced hacking

+ or -

1-

Your first question asks how you should write$\displaystyle \frac{-\vec a +3\vec b-2 \vec c}{7}$, when $\displaystyle \vec c= \binom 12$

Of the two answers you give, the one with the $\displaystyle +$ sign is correct:$\displaystyle \frac{-\vec a +3\vec b+ \binom{-2}{-4}}{7}$

since you have taken the $\displaystyle -$ sign into account by mutliplying $\displaystyle \binom12$ by $\displaystyle -2$ to get $\displaystyle \binom{-2}{-4}$.

Originally Posted by

**darklight** 2- 2MN=6i how to solve this ?

(MN and i are in vector with an index "-->")

Your question seems to ask: How do I solve

$\displaystyle 2 -2\vec{MN} =6\vec i$

If so, it doesn't make sense, since $\displaystyle 2$ is a scalar and $\displaystyle \vec{MN}$ and $\displaystyle \vec i$ are vectors. You can't add vectors and scalars like this.

What did you really mean?

Grandad