Factorise:

The given expression is $2 x^{2}-17 x-30$.

Find two numbers that follow the conditions given below:

Sum $=-17$

Product $=-30 \times 2=-60$

Clearly, the numbers are $-20$ and 3 .

$2 x^{2}-17 x-30=2 x^{2}-20 x+3 x-30$

$=2 x(x-10)+3(x-10)$

$=(2 x+3)(x-10)$