To find the value of a, we express the general points of lines l and m in component form:
\(Line l: r = (a + λ)i + (2 - 2λ)j + (3 + 3λ)k\)
\(Line m: r = (2 + 2μ)i + (1 - μ)j + (2 + μ)k\)
Since the lines intersect, equate the corresponding components:
\(1. a + λ = 2 + 2μ\)
\(2. 2 - 2λ = 1 - μ\)
\(3. 3 + 3λ = 2 + μ\)
From equation (2):
\(μ = 2 - 2λ - 1 = 1 - 2λ\)
\(Substitute μ = 1 - 2λ into equation (1):\)
\(a + λ = 2 + 2(1 - 2λ)\)
\(a + λ = 2 + 2 - 4λ\)
\(a + λ = 4 - 4λ\)
\(5λ = 4 - a\)
\(λ = \frac{4 - a}{5}\)
\(Substitute λ = \frac{4 - a}{5} into equation (3):\)
\(3 + 3\left(\frac{4 - a}{5}\right) = 2 + (1 - 2\left(\frac{4 - a}{5}\right))\)
\(3 + \frac{12 - 3a}{5} = 2 + 1 - \frac{8 - 2a}{5}\)
\(3 + \frac{12 - 3a}{5} = 3 - \frac{8 - 2a}{5}\)
Multiply through by 5 to clear fractions:
\(15 + 12 - 3a = 15 - 8 + 2a\)
\(27 - 3a = 7 + 2a\)
\(5a = 20\)
\(a = -6\)