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Box Method for Factoring Factoring expressions in the form of ax2+bx+c Box Method for Factoring We are going to factor the expression 15x2 -7x-2 First draw a box and divide into quarters. Box Method for Factoring Now we are going to place the terms of the expression into the box. Look at the expression: 15x2 -7x-2 Place the 15x2 in the top left box. Place the -2 in the bottom right box. 15x2 -2 Box Method for Factoring 15x2 -7x-2 Now we are going to multiply the coefficient of the first term by the constant. (15)(-2) = -30 15x2 -2 Box Method for Factoring Now we are going to list the factors of 30. 30 1 30 2 15 3 10 5 6 Are there any pair of numbers that would equal -7? Box Method for Factoring We just found the factors of -30 that have a sum of -7! We will place those factors in the box with an “x” It doesn’t matter which box you put them in. 15x2 -10x 3x -2 Box Method for Factoring Now we are going to pull out the common factors from each row and column. Last sign out of the box determines the sign. 3x -2 5x 15x2 -10x 1 3x -2 Box Method for Factoring We now have the factors of 15x2 -7x-2 The factors are: (5x + 1)(3x - 2)