Answer:
(-2, 3)
Step-by-step explanation:
4x + 5y = 7
3x - 2y = -12
Let's solve this by elimination. We want to eliminate one variable at a time. This means we need to multiply the equations to create a common multiple to cancel out a variable.
Let's work with y.
5y and -2y: For these values to cancel out, we need to multiply each term to create a common multiple.
2(4x + 5y = 7)
5(3x - 2y = -12)
Multiply.
8x + 10y = 14
15x - 10y = -60
Eliminate.
23x = -46
Divide both sides by 23.
x = -2
Now that we know x, let's plug it back into one of equations to find y.
4x + 5y = 7
4(-2) + 5y = 7
Multiply.
-8 + 5y = 7
Add.
5y = 15
Divide.
y = 3
Now we know x and y; let's plug both back into the equation we have not checked yet.
3x - 2y = -12
3(-2) - 2(3) = -12
Multiply.
-6 - 6 = -12
Subtract.
-12 = -12
Your solution is correct.
(-2, 3)
Hope this helps!
Answer:
decay
growth
decay
i'm sure im in k12 for 9 th grade please tell me if i'm right
Step-by-step explanation:
Answer: 648
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Explanation:
We have this set of digits: {0, 1, 2, 3, 4, 5, 6, 7, 8, 9}
From that set, we can only pick three items. We cannot select the same digit twice.
Consider a blank three digit number such that it is composed of slot A, slot B, slot C.
Since the number must be larger than 100, this means that we cannot select 0 as the first digit. We go from a pool of 10 digits to 10-1 = 9 digits for our first selection.
In other words, we have this subset to select from
{1, 2, 3, 4, 5, 6, 7, 8, 9}
So we have 9 choices for slot A.
For slot B, we also have 9 choices since 0 is now included. For instance, if we selected the digit '4' then we have this subset of choices left over: {0, 1, 2, 3, 5, 6, 7, 8, 9} which is exactly 9 items.
For slot C, we have 9-1 = 8 items left to choose from. For example: If we choose '4' for slot A, and '2' for slot B, then we have this subset to choose from: {0, 1, 3, 5, 6, 7, 8, 9} exactly 8 items
In summary so far, we have...
9 choices for slot A
9 choices for slot B
8 choices for slot C
Giving a total of 9*9*8=81*8=648 different three digit numbers. You'll notice that I'm using the counting principle which allows for the multiplication to happen. Think of a probability tree.
