Question

Answer 1

a) \(3x\left(12x-4\right)-9x\left(4x-3\right)=30\)

\(36x^2-12x-36x^2+27x=30\)

\(15x=30\)

\(x=\dfrac{30}{15}\)

\(x=2\)

b) \(x\left(5-2x\right)+2x\left(x-1\right)=15\)

\(5x-2x^2+2x^2-2x=15\)

\(3x=15\)

\(x=\dfrac{15}{3}\)

\(x=5\)

Answer 2

a.

\(3x\left(12x-4\right)-9x\left(4x-3\right)=30\)

\(\Leftrightarrow36x^2-12x-\left(36x^2-27x\right)=30\)

\(\Leftrightarrow36x^2-12x-36x^2+27x=30\)

\(\Leftrightarrow15x=30\)

\(\Leftrightarrow x=2\)

b.

\(x\left(5-2x\right)+2x\left(x-1\right)=15\)

\(\Leftrightarrow5x-2x^2+2x^2-2x=15\)

\(\Leftrightarrow3x=15\)

\(\Leftrightarrow x=5\)