
We know that

because of the Pythagorean trig identity

.
Answer:
x^3-8
Step-by-step explanation:
x^3+2x^2+4x + -2x^2-4x-8
+2x^2 and -2x^2 cancel out
+4x and -4x cancel out
Answer:
They are all true
Step-by-step explanation:
1. 3² +4² = 5²
3x3 + 4x4 = 5x5
9 + 16 = 25
25 = 25
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2. 6² + 8² = 10²
36 + 64 = 100
100 = 100
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3. 9² + 12² = 15²
81 + 144 = 225
225 = 225
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4. 5² +12² =13²
25 + 144 = 169
169 =169
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the answer is 2.7. 5.0 - 2.3 = 2.7