Consider the linear homogeneous system x? = p11(t)x + p12(t)y, y? = p21(t)x + p22(t)y. Show that if x = x1(t), y = y1(t) and x = x2(t), y = y2(t) are two solutions of the given system, then x = c1x1(t) + c2x2(t), y = c1y1(t) + c2y2(t) is also a solution for any constants c1 and c2. This is the principle of superposition.

19.side- angle- side

20. angle- side- angle

step-by-step explanation:

c. y = 1/4 x + 5

step-by-step explanation:

first, put the equation of the line on the graph into slope-intercept form

(y = mx + b):   y = -4x + 8

second, a perpendicular line has to have "an opposite/reciprocal slope" to the original slope. so, find the "m" value in your original equation (it's -4, right? )

original slope: m = -4   perpendicular slope: change the sign to its opposite and find the reciprocal ("flip" the number)

new slope is now positive (b/c the original slope was negative 4), and it's 1/4 (not the original slope of 4 or 4/1)

this may not be at all, but i use the same website you're using for school, and if i'm stuck doing one of these i try to look for it on the section.