Answer:
Multiply x + y = 3 by 3 and add it to -3x - 2y = -7
Step-by-step explanation:
When using elimination to solve a system of equations, you multiply one equation by some number. The reason for doing this is that when you add it to the second equation, you want one variable to cancel out. When one variable cancels out (in this case x), you can solve for the other variable (in this case y). I will show this:
3(x + y = 3) = 3x + 3y = 9
3x + 3y = 9
+ -3x + -2y = -7
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y = 2
Now, knowing that y = 2, you can substitute y=2 into either equation to solve for x.
-3x - 2(2) = -7
-3x -4 = -7
-3x = -3
x = 1 | to double check (1, 2) as your answer plug these values into both equations
Finding this solution would not have been possible if not for cancelling out the x's above. The other three are wrong because none of the other options cancels out one of the variables.
500/20 = 25kcal per piece
8 * 25 = 200kcal.....yes, he is able to have 8 pieces
Answer:81.31
Step-by-step explanation:
This could be a situation in which items are both bought and sold. In calculating the inventory, positive numbers represent items bought, negative numbers represent items sold and 0 would be no items in the inventory.
Another type of situation would be the displacement of an object from the original position. Where 0 would represent the original/starting position, positive values would represent distance moved forward, negative values represent distance moved backwards.
