Answer:
the answer is C
Step-by-step explanation:
<span><em />
3x+y=5</span>
<span /><span>2x-2y=22 ...............2(x-y)=22 ⇒ x-y=11</span><span><em /></span>
<span><em>3x+y=5</em></span>
<span /><span><em><u>x-y=11 </u> </em>(+)</span>
<span />3x+x+y-y=11+5
<span>4x=16 /:4</span>
<span /><em>x=4</em>
x-y=11
4-y=11
-y=7 /*(-1)
<em>y=-7</em>
<span><em></em></span>
First we need to find the slope of line k. Using the slope formula, we fill in accordingly:

. The slope is -3/2. The slope of a line that is perpendicular to line k will have the opposite sign (so, positive) and will be the reciprocal of the line k's slope (so, 2/3). You could also say, more "mathematically legal", that the product of the slopes of perpendicular lines is -1, but it's easier to just say that they are opposite reciprocals. The slope you're looking for is 2/3. Choice 3 above.
Use a system of equations.
(x=# of small dogs, y=# of big dogs)
x+y=9 (times by -5) -5x-5y=-45
5x+8y=51
Then add the equations together and the x's cancel.
3y=6
y=2
So he walked 2 big dogs and 7 little dogs.