Question

розв'яжіть рівняння 3(х^2-1)/7-x+9/6=x+6/3 помогите пж

Answer 1

$\dfrac{3(x^{2}-1) }{7}-\dfrac{x+9}{6}=\dfrac{x+6}{3} \\\\\dfrac{3(x^{2}-1) }{7}=\dfrac{x+6}{3}+\dfrac{x+9}{6}\\\\\dfrac{3(x^{2}-1) }{7}=\dfrac{2x+12+x+9}{6}\\\\\dfrac{3(x^{2}-1) }{7}=\dfrac{3x+21}{6}\\\\18(x^{2} -1)=7(3x+21)\\\\18x^{2}-18-21x-147=0\\\\18x^{2} -21x-165=0\\\\6x^{2}-7x-55=0\\\\D=(-7)^{2}-4\cdot 6\cdot (-55)=49+1320=1369=37^{2}$

$x_{1} =\dfrac{7-37}{12}=-\dfrac{30}{12} =-2,5\\\\x_{2}=\dfrac{7+37}{12}=\dfrac{44}{12}=3\dfrac{2}{3}$