If y=-4 when x=10 find y when x=2

X = y x z
10 = (-4) x z
Z= -10/4 = -5/2

So now we know z = -5/2
we can find y when x = 2

Again x = y x z   
        
2 = y x (-5/2)
So y =2  x ( -2/5)  = - 4/5

Double check:
x = yx (x = 2 , y = -4/5), z = -5/2)                          
2 = (-4/5) x (-5/2) = 20/10 = 2 

when x = 2, y = -4/5

$7.50x+$4.50y=midk it's been awhile since i've done one of these

This makes absolutely no sense at all young man/women