"Answer: 11x - 8y = -9
Explanation:
For this exercise you need to remember:
1) The multiplication of signs:
(+) (+) = +
(-) (-) = +
(-) (+) = -
(+) (-) = -
2) By definition, like terms contain the same variables with the same exponent.
Then know this, and given the equations:
8x - 4y = -4 and -3x + 4y = 5
You must subtract the like terms, which means that you must subtract the numerical coefficients of each term.
Then, you get the result is:
8x - 4y = -4
-3x + 4y = 5
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8x - (-3x) - 4y - 4y = - 4y -5
8x + 3x - 8y = -9
11x - 8y = -9"