If two lines intersect, then the pair of linear equations representing these lines will have ______. 

A pair of linear equations having a unique solution would represent two intersecting lines. 

For example:

If the two linear equations are of the form:

${\mathrm{a}}_1\mathrm{x}+{\mathrm{b}}_1\mathrm{x}+{\mathrm{c}}_1=0$

${\mathrm{a}}_2\mathrm{x}+{\mathrm{b}}_2\mathrm{x}+{\mathrm{c}}_2=0$

Then the system of equation will have a unique solution if:

$\frac{{\mathrm{a}}_1}{{\mathrm{a}}_2}\ne \frac{{\mathrm{b}}_1}{{\mathrm{b}}_2}\ne \frac{{\mathrm{c}}_1}{{\mathrm{c}}_2}$ 

Such equations would result in intersecting lines when plotted on a graph.