ACT Preparation / Unit 8 ACT 0704 short lesson, about 20 seconds
The Square of a Binomial
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The idea
The square of a binomial is (a + b)² = a² + 2ab + b², and (a − b)² = a² − 2ab + b².
In practice
(x + 4)² = x² + 8x + 16.
Where people slip
(a + b)² is not a² + b²: (2 + 3)² is 25, but 2² + 3² is 13.
Your place on the trail
Every lesson rests on earlier ones and opens later ones. Tap any to jump.
Builds on
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