Answer:
42
Step-by-step explanation:
It's just a distribution property where the given value of each variables (a, b, c, d) are being distributed to the given equation:
7a2-3ac+d2
7(2)(2) - 3(2)(-3) + (-2)(2)
28 + 18 - 4 = 42
Y=3x+1
-2x+y=6
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