Is the relationship shown by the data linear? if so, model the data with an equation. x= -7, -5, -3 ,-1 , y = 5, 9, 13, 17

The data is linear as the x and y are both increasing at a set amount. 
X increases by 2 each time Y increases by 4. 
Our slope would be 2x because every time x goes up 1 y goes up 2. 
With that knowledge I can figure that if you increased the point -1,17 by the slope to get 0,21 that would be the  y intercept. 
Thus the equation should be y=2x+21

Arhombus is a quadrilateral.