If -15 is equal to -0.2x, then 15/0.2=75
x=75
Answer:
Triangle A and Triangle B
Vertical line are represented by x = a number....that number being the x value in ur set of points
so ur equation is : x = -7
(a-b) X (a+b)
= aXa - bXa +aXb -bXb (distributing)
Now, cross product of a vector with itself = 0
so, aXa = 0, bXb = 0
Also, aXb = - bXa
so,
(a-b) X (a+b) = 0 + aXb + aXb + 0
= 2aXb
hence, proved :)
