Answer:
100
Step-by-step explanation:
To solve this, first, rewrite x(x+8)=9 in a different form. If you multiply x+8 by x and subtract 9 from both sides, you get x^2 + 8x - 9 = 0. Next, plug these numbers into b^2 - 4ac. You would then get 8^2 - 4(1)(-9). Siplified, you end up with 64 + 36, or 100.
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