On a busy day, a shop sells a total of 15 desks and chairs for a total amount of $960.The desks sell for $120 each and the chairs sell for $50 each. (a) Express the information as two equations. Let d equal the number of desks and let c equal the number of chairs.
(b) Solve the equations simultaneously to find how many of each were sold.

- sold 15 desks + chairs

- each desk is $120

- each chair is $50

- total amount is $960

- desk = d

- chairs = c

(a) i/ d + c = 15

ii/ 120d + 50c = 960

(b) d+c = 15 (1)

120d + 50c = 960 (2)

from (1) d+c = 15

c = 15-d (3)

substitute (3) into (2)

120d + 50c = 960

120d + 50(15-d) = 960

120d + 750 - 50d = 960

120d - 50d = 960 - 750

70d = 210

d = 210/70

d = 3

substitute d=3 into (3)

c = 15-d

c = 15-3

c = 12

thus, 3 desks and 12 chairs were sold

ummm seems that u didnt post the attachement !

guess at question:

a vertical line intersects the graph of g(x,y) = 0 at two points. what conclusion follows about the function f(x) implicitly defined by g(x,f(x)) = 0?

the domain of f(x) cannot include the x coordinate of any such vertical line.

informally, f(x) is not a function, and

g(x,y)=0 cannot be solved for y uniquely.

the relation r = {(x,y) such that g(x,y) = 0} is a function if

for all (a,b) ∊ r and (c,d) ∊ r, a=c implies b=d.

step-by-step explanation: