Bài 1: Giải phương trình:
a) (2x + 3)2 - 3 (x - 4) (x + 4)= (x - 2)2 + 1
b) (3x - 2) (9x2 + 6x + 4) - (3x - 1) (9x2 - 3x + 1) = x - 4
c) x (x - 1) - (x - 3) (x + 4) = 5x
d) (2x + 1) (2x - 1) = 4x (x - 7) - 3x
Mng giúp Bơ nhaaa
Camon và hứa trả công ạaa
a) \(\left(2x+3\right)^2-3\left(x-4\right)\left(x+4\right)=\left(x-2\right)^2+1\)
\(\Leftrightarrow4x^2+12x+9-3\left(x^2-16\right)=x^2-4x+4+1\)
\(\Leftrightarrow4x^2+12x+9-3x^2+48=x^2-4x+5\)
\(\Leftrightarrow x^2+12x+57=x^2-4x+5\)
\(\Leftrightarrow16x+52=0\)
\(\Leftrightarrow x=-\frac{13}{4}\)
b) \(\left(3x-2\right)\left(9x^2+6x+4\right)-\left(3x-1\right)\left(9x^2-3x+1\right)=x-4\)
\(\Leftrightarrow\)Xem lại đề !
c) \(x\left(x-1\right)-\left(x-3\right)\left(x+4\right)=5x\)
\(\Leftrightarrow x^2-x-x^2-x+12=5x\)
\(\Leftrightarrow-2x+12=5x\)
\(\Leftrightarrow7x-12=0\)
\(\Leftrightarrow x=\frac{12}{7}\)
d) \(\left(2x+1\right)\left(2x-1\right)=4x\left(x-7\right)-3x\)
\(\Leftrightarrow4x^2-1=4x^2-28x-3x\)
\(\Leftrightarrow28x+3x-1=0\)
\(\Leftrightarrow31x-1=0\)
\(\Leftrightarrow x=\frac{1}{31}\)
a) (2x + 3)2 - 3 (x - 4) (x + 4)= (x - 2)2 + 1
<=> 4x^2 + 12x + 9 - 3(x^2 - 16) = x^2 - 4x + 4 + 1
<=> 4x^2 + 12x + 9 - 3x^2 + 48 = x^2 - 4x + 5
<=> x^2 + 12x + 57 = x^2 - 4x + 5
<=> x^2 - x^2 + 12x + 4x + 57 - 5 = 0
<=> 16x + 52 = 0
<=> 16x = -52
<=> x = -13/4