The equivalent equation is x² + 20x = -102
<h3>
Simplification of quadratic equation</h3>
The equivalent equation can be obtained by factorizing or simplifying the given quadratic equation as shown below;
x² + 20x + 81 = -21
<em>collect similar terms together</em>
x² + 20x + 81 + 21 = 0
x² + 20x + 102 = 0
The equation can also be written as x² + 20x = -102
Thus, the equivalent equation is x² + 20x = -102
Learn more about simplification of quadratic equation here: brainly.com/question/1214333
Answer:
Step-by-step explanation:⇔
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are the measures but if you forgot to add the picture then... who knows
A because I have done this before