126. Solving a chemistry problem

For the chromatographic determination of nickel on paper impregnated with a solution of dimethyldioxime, three standard solutions were prepared. To do this, a portion of m(g) NiCl2*6H2O was dissolved in a 50.0 ml volumetric flask. From this flask took 5.0; 10.0 and 20.0 ml and diluted in 50.0 ml flasks. The test solution was also diluted in a 50.0 ml volumetric flask.
Construct a calibration graph in the coordinates h - mNi and determine the nickel content (mg) in the test solution if the peak height of the standard solutions is h1, h2 and h3, and the peak height of the test solution is hx (mm).

Variant m, g h1 h2 h3 hx
7.10 0.2780 28.5 42.3 70.0 47.5