How do you factor #b^ { 2} - 3b - 4?#

1 Answer
Mia
Nov 25, 2016

#(b-4)(b+1)#

Explanation:

The algebraic expression #b^2-3b-4" "#can be factorized using
#" "#
the trial and error method, in other words, the idea is to find two
#" "#
integers #c and d# whose sum #" "color(blue)S = -3" "# and their
#" "#
product is #color(blue)P = -4#
#" "#
Trial and Error Factorization :
#" "#
#X^2+color(blue)SX+color(blue)P =(x+c)(x+d)#

For the expression#" "b^2-3b-4" "#,the two integers satisfying the
#" "#
#color(blue)S# and #color(blue)P# requirements are #c=-4 and d=+1#
#" "#
Therefore,
#" "#
#b^2-3b-4=(b-4)(b+1) #

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