Let the number of text messages be represented by X.
Then the total cost of David's cell phone adds up to

Since the total cost of David's phone equals $91.40, we get the following equation.

Subtract 50 on both sides

Divide both sides by 0.45

Therefore David has send 92 text messages.
There aren't any specified coordinates?
Answer:
this is the answer but it must be 20 character long
8x+3
Answer:
a) $49.48
b) $220921.91
Step-by-step explanation:
(a) 4 yd @ $12.37 per yd = 4 x $12.37 = $49.48
(b) 271 yd @ 815.21 per yd = 271 x $815.21 = $220921.91
(c) 20% yd @ $4.95 per yd : Here the nunber of yards are missing. Hence could not be answer . However if number of yards is x . The answer would be
20% of 4.95x
(20%=0.20)
0.20 × 4.95x