2.67 repeating as a fraction in simplified
1 answer:
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Answer: C. (-4, -2)
<u>Step-by-step explanation:</u>
First, eliminate one of the variables and solve for the remaining variable:
2x - 5y = 2 → 3(2x - 5y = 2) → 6x - 15y = 6
3x + 2y = -16 → -2(3x + 2y = -16) → <u> -6x - 4y = 32</u>
-19y = 38
y = -2
Next, replace "y" with -2 into either of the original equations to solve for x:
2x - 5y = 2
2x - 5(-2) = 2
2x + 10 = 2
2x = -8
x = -4
x = -4, y = -2
<u>Check:</u>
Plug in the x- and y-values into the other original equation:
3x + 2y = -16
3(-4) + 2(-2) = -16
-12 + -4 = -16
-16 = -16
9514 1404 393
Answer:
C, A, A
Step-by-step explanation:
In general, you ...
- identify the coefficients of one of the variables
- swap them, and negate one of them
- multiply the corresponding equations by the "adjusted" coefficients.
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In problem 1, the x-coefficients are 8 and 2. A common factor of 2 can be removed so that we're dealing with the numbers 4 and 1. Assuming we want to multiply one of the equations by 1, leaving it unchanged, the value we want to multiply by will be -4. After we swap the coefficients, that multiplier is associated with equation 2:
multiply equation 2 by -4 . . . (eliminates x)
Likewise, the y-coefficients in problem 1 are -1 and 3. Again, if we want to multiply one of the equations by 1, leaving it unchanged, the coefficient we will change the sign of is -1 (becomes 1). After we swap the coefficients, the multiplier 3 is associated with equation 1:
multiply equation 1 by 3 . . . (eliminates y)
These two choices are B and A, respectively, so the one that does NOT work for problem 1 is choice C, as indicated below.
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The other problems are worked in a similar fashion.
Answer:
(x, y) = (-0.6, 0.8) or (1, 4)
Step-by-step explanation:
Use the second equation to substitute for y in the first.
(x -1)² +((2x +2) -2)² = 4
x -2x +1 + 4x² = 4 . . . . . . . eliminate parentheses
5x² -2x -3 = 0 . . . . . . . . . . subtract 4, collect terms
Now we can rearrange the middle term to ease factoring by grouping.
(5x² -5x) +(3x -3) = 0
5x(x -1) +3(x -1) = 0
(5x +3)(x -1) = 0
The values of x that make these factors zero are ...
x = -3/5, x = 1
The corresponding values of y are ...
y = 2(-3/5)+2 = 4/5 . . . . for x = -3/5
y = 2(1) +2 = 4 . . . . . . . . for x = 1
The solutions are: (x, y) = (-3/5, 4/5) or (1, 4).
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A graphing calculator verifies these solutions.
