Question

2. Giải phương trình:

a) \(4x(2x+3) - x(8x-1) = 5(x+2)\)

b) \(\frac{12x+5}{3} = \frac{2x-7}{4}\)

c) \((3x-5)(3x+5) - x(9x-1) = 4\)

d) \(\frac{5x-4}{2} = \frac{16x+1}{7}\)

Answer 1

\(a) 4x(2x+3)-x(8x-1)=5(x+2)\)

\(8x^2 + 12x - 8x^2 + x = 5x + 10\)

\(13x - 5x = 10\)
\( 8x = 10 \)

\(x = \frac{10}{8} = \frac{5}{4}\)

\(b) \frac{12x+5}{3}=\frac{2x-7}{4}\)

\(48x + 20 = 6x - 21\)

\(48x - 6x = -21 - 20\)

\(42x = -41\)

\(x = -\frac{41}{42}\)

\(c) (3x-5)(3x+5)-x(9x-1)=4\)

\(9x^2 - 25 - 9x^2 + x = 4\)

\(x - 25 = 4\)

\(x = 29 \)

\(d) \frac{5x-4}{2}=\frac{16x+1}{7}\)

\(7(5x-4) = 2(16x+1)\)

\(35x - 28 = 32x + 2\)

\(35x - 32x = 2 + 28\)

\(3x = 30\)

\(x = 10\)

Học tốt nha=)