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FOIL
CONCEPTS
FOIL Calculation
• (ax + b)(cx + d) = acx² + bcx + adx + bd
• Typically, the bc & ad terms can be combined, but not always
PRACTICE PROBLEMS
Question 1 When (x + 1)⁴ is expanded and like terms are combined, what is the coefficient of x²?
-- Answer -- 6
(x + 1)⁴ = (x + 1)² * (x + 1)²
= (x² + 2x + 1) * (x² + 2x + 1)
x² terms => (1)(x²) + (2x)(2x) + (1)(x²)
= 6x²
ACT PRACTICE PROBLEMS
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