To simplify this all you need to do is distribute the 4x across each term in the parenthesis
Answer:

Step-by-step explanation:

Answer:
a) The cost of ribeye steak dinners is $ 16.96.
b) The cost of grilled salmon dinners is $ 23.37.
Explanation:
Let the cost for ribeye steak dinners be m and cost for grilled salmon dinners be n.
A waitress sold 10 ribeye steak dinners and 18 grilled salmon dinners, totaling $590.39 on a particular day.
So, we have
10 m + 18 n = 590.39 -------equation 1
Another day she sold 22 ribeye steak dinners and 9 grilled salmon dinners, totaling $583.49
So, we have
22 m + 9 n = 583.49 -------equation 2
equation 2 x 2
44 m + 18 n = 1166.98 -------equation 3
equation 3 - equation 1
44 m + 18 n - ( 10 m + 18 n ) = 1166.98 - 590.39
m = 16.96 $
Substituting in equation 1
22 x 16.96 + 9 n = 583.49
n = 23.37 $
a) The cost of ribeye steak dinners is $ 16.96.
b) The cost of grilled salmon dinners is $ 23.37.
The answer is -31 over 12.
10% of 18 tonnes = 1.8 tonnes
30% of 18 tonnes = 5.4 tonnes
18 - 5.4 tonnes = 12.6 tonnes