A rectangle has a length of \( 2 x + 5 \) and width of \( x - 2 \) . Which polynomial represents the area of the rectangle?
Question
Answer
Area of the rectangle is \(2x^2+ x- 10\)
Expand \( ( 2 x + 5 ) ( x - 2 ) : \quad 2 x ^ { 2 } + x - 10\)
\(( 2 x + 5 ) ( x - 2 ) \)
Apply FOIL method: \( ( a + b ) ( c + d ) = a c + a d + b c + b d \)
\( ( 2 x + 5 ) ( x - 2 ) = 2 x x + 2 x ( - 2 ) + 5 x + 5 ( - 2 ) \)
\( = 2 x x + 2 x ( - 2 ) + 5 x + 5 ( - 2 ) \)
Simplify \( 2 x x + 2 x ( - 2 ) + 5 x + 5 ( - 2 ) : 2 x ^ { 2 } + x - 10 \)
\( = 2 x ^ { 2 } + x - 10\)