Answer:
0
Step-by-step explanation:
-3x +4y = 20 Multiply this equation by 2.
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6x + 3y = 15
-6x + 8y = 40 Notice that -3 becomes -6, 4 becomes 8 and 20 becomes 40
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11y = 55 The xs have disappeared. Divide by 11
y = 55/11
y = 5
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6x + 3y = 15
6x + 3*5 = 15
6x + 15 = 15
6x = 15 - 15
6x = 0
6x/6 = 0/6
x =0
