In an experiment to determine the young’s modulus, steel wires of five different lengths (1,2,3,4 and 5 m) but of same cross section ${\text{(2mm}}^2)$ were taken and curves between extension and load were obtained.  The slope of the curves were plotted with (extension/ load) along  $y$ axis and the wire length along   $x$axis. If the young’s modulus of given steel wires $x\times {10}^9{\text{\hspace{0.17em}Nm}}^{-2}$ , then the value of x is