\(8.7x\left(x-2\right)-5\left(x-1\right)=21x^2-14x^2+3\)
\(7x^2-19x+5=7x^2+3\)
\(7x^2-19x=7x^2+3-5\)
\(7x^2-19x=7x^2-2\)
\(-19x=7x^2-2-7x^2\)
\(-19x=-2\)
\(x=-2:\left(-19\right)\)
\(x=\dfrac{2}{19}.\)
\(Vậy...\)
\(9.3\left(5x-1\right)-x\left(x-2\right)+x^2-13x=7\)
\(4x-3=7\)
\(4x=7+3\)
\(4x=10\)
\(x=10:4\)
\(x=\dfrac{5}{2}.\)
\(Vậy...\)
\(10.\dfrac{1}{5}x\left(10x-15\right)-2x\left(x-5\right)=12\)
\(x\left(10x-15\right)-10x\left(x-5\right)=60\)
\(35x=60\)
\(x=60:35\)
\(x=\dfrac{12}{7}.\)
\(Vậy...\)
Giup mình bài 8,9,10
