Ответ учителя по предмету Алгебра
x^2 + 6x — 9 > 0
x^2 + 6x — 9 = 0
D = 36 + 4*9 = 72
√D = 6√2
x1 = ( — 6 + 6√2)/2 = — 3 + 3√2;
x2 = ( — 6 — 6√2)/2 = — 3 — 3√2
+ — +
————-( — 3 — 3√2) ——————( — 3 + 3√2) —————> x
x ∈ ( — ∞ ; — 3 — 3 √2) ∪ ( — 3 + 3√2; + ∞)
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