Answer:
It's C.) 5y = 5 not B
They want you to multiply -2 by the bottom equation which is
x - 2y = -1
So you will be taking each individual number in this equation and multiplying it by -2
Remember when multiplying a negative number by another negative number it will create a positive one
x - 2y = -1
The underlined numbers in the equation correlate with the numbers I am multiplying by -2
x * -2 = -2x
-2y * -2 = 4y
-1 * -2 = 2
So the new equation would be -2x + 4y = 2
now add
2x + y = 3
and
-2x + 4y = 2
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1st equation 2x + y = 3
2nd equation -2x + 4y = 2
1 2 3
(2x + -2x) + (y + 4y) = (3 + 2)
1. 2x and -2x cancel each other out and you get 0
2. y + 4y is just 1y + 4y which is 5y
3. and 3 + 2 is 5
which leaves us with
5y = 5
