Đáp án:
Bài 1
a)(4x−3)(3x+2)−(6x+1)(2x−5)+1
= 12x²+8x-9x-6-(12x²-30x+2x+5)+1
= 12x²+8x-9x-6-12x²+28x+5+1
=27x+0=27x
Bài 2
a)(3x+1)²+(5x−2)²=34(x+2)(x−2)
⇒9x²+6x+1+25x²-20x+4=34(x²-4)
⇒34x²-14x+5=34x²-136
⇒-14x+5=-136
⇒x=$\frac{141}{14}$
b)x³+3x²+3x+28=0
⇒x³+3x²+3x+1+27=0
⇒(x+1)³+27=0
⇒(x+1)³=-27=(-3)²
⇒x+1=-3
⇒x=-4