X=numbers of hammers
y=numbers of scewdrivers
f(x,y)= total cost in $
f(x,y)=11x+6.65y
f(4,7)=4(11)+6.65(7)=44+46.55=90.55
Sol: an expresion for the total cost of the tools is f(x,y)=11x+6.65 y;
x=number of hammers
y= number of scewdrivers.
The total cost is $90.55
L.H.S is already equal, so just subtract 1st equation from second,
2y = 12
y = 6
Now, substitute it in 1st equation,
2(6) = 4x + 8
4x = 12 - 8
x = 4/4
x = 1
In short, Your Answer would be Option C) (1, 6)
Hope this helps!
It can be the last one, 827 over 1120
Hope that helps