First find the side that has a exact number which would be the bottom 28cm then look at the opposite side (2x+10) in order to find x subtract 10 from 28 which gives you 18, now 2x means x multiplied by 2 so what multiplied by 2 = 18? 9 meaning <u><em>x=9</em></u>. Now you are going to want to plug 9 in to your short side (x-3) once you plug it in it should look like this 9-3 and 9-3=6 meaning the short side is 6cm. In order for you to find the perimeter you have to add the sides together so 28+28+6+6 wich <u><em>=68</em></u> and in order for you to find the area you have to multiply the length and the width so 28x6 which is <em><u>168</u></em>.
A line that is perpendicular to it has a slope that is an opposite reciprocal, which in this case is -1/3. Now you use point slope form which is y-y1=m(x-x1) that would be y+5=-1/3(x-6). Distribute the -1/3 and get y+5= -1/3 x+ 2. Subtract 5 from both sides and get y=-1/3 x - 3