Question

1.Tìm x,biết:

a)6x(4x-3)+8x(5-3x)=43

b)(1-7x)(2x-3)-(14x-9)(5-x)=30

Answer 1

a/

\(\Leftrightarrow24x^2-18x+40x-24x^2=43\)

\(\Leftrightarrow22x=43\)

\(\Leftrightarrow x=\frac{43}{22}\)

b/ \(\Leftrightarrow23x-3-14x^2-\left(79x-14x^2-45\right)=30\)

\(\Leftrightarrow-56x=-12\)

\(\Rightarrow x=\frac{3}{14}\)

Answer 2

Bài giải

a, \(6x\left(4x-3\right)+8x\left(5-3x\right)=43\)

\(24x^2-18x+40x-24x^2=43\)

\(22x=43\)

\(x=\frac{43}{22}\)

b, \(\left(1-7x\right)\left(2x-3\right)-\left(14x-9\right)\left(5-x\right)=30\)

\(2x-14x^2-3+21x-\left(70x-45-14x^2+9x\right)=30\)

\(-56x+42=30\)

\(-56x=-12\)

\(x=\frac{3}{14}\)