Question

resolva em R:
(x-1)(2x+1)=(x-1)(x+4)

Answer 1

(x-1). (2x+1)=(x-1). (x+4)
3x^2+x-2x-1= x^2+4x-x-4
3x^2-x^2+x-2x-4x+x-1+4=0
2x^2+4x+3=0

Answer 2

(x-1)(2x+1)=(x-1)(x+4)
$2 x^{2} + x -2x-1= x^{2} +4x-x-4 \\ 2 x^{2} -x- x^{2} -3x-1+4=0 \\ x^{2} -4x +3=0 \\\\ DELTA\\\\ (-4)^{2} -4*1*3\\ 16-12\\ 4 \\\\VALOR\ X:\\\\ \frac{-(-4)+- \sqrt{4} }{2} \\ \frac{4+- 2 }{2} \\\\ x'=4+2=6/2= \3\\ x''=4-2=2/2= \1$
X'= 3
X''= 1