This is a difference of squares problem. You just have to make sure every term is a perfect square and that there is subtraction in the problem.
Step-by-step explanation:
= -1 × 729
= -729
<em>Hi!</em>
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<em>These can be set up as systems of equations.</em>
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<em>Let b = the number of birds, and let d = the number of dogs.</em>
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<em>b + d = 21</em>
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<em>2b + 4d = 76 (this is because birds have 2 legs and dogs have 4 legs.)</em>
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<em>You can solve this using either elimination or substitution.</em>
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<em>Consider marking brainliest.</em>
(8)(2)+4(8)(-5)(2)(2)
The answer is -624
