Simple constraint

If p₁ follows p₀, then p₁ gets its coordinates from the following set of equations:

Failed to parse (Conversion error. Server ("/media/api/rest_") reported: "Cannot get mml. TeX parse error: Double subscripts: use braces to clarify"): {\displaystyle d_{p}=p_{0}_{x}-p_{1}_{x}}

Failed to parse (Conversion error. Server ("/media/api/rest_") reported: "Cannot get mml. TeX parse error: Double subscripts: use braces to clarify"): {\displaystyle d_{y}=p_{0}_{y}-p_{1}_{y}}

$l_{1}=d_{x}^{2}+d_{y}^{2}$

Failed to parse (Conversion error. Server ("/media/api/rest_") reported: "Cannot get mml. TeX parse error: Double subscripts: use braces to clarify"): {\displaystyle p_{1}_{d}x=d_{x}/l_{1}*r-d_{x}}

Failed to parse (Conversion error. Server ("/media/api/rest_") reported: "Cannot get mml. TeX parse error: Double subscripts: use braces to clarify"): {\displaystyle p_{1}_{d}y=d_{y}/l_{1}*r-d_{y}}

, and finally

Failed to parse (Conversion error. Server ("/media/api/rest_") reported: "Cannot get mml. TeX parse error: Double subscripts: use braces to clarify"): {\displaystyle p_{1}_{x}+=p_{1}_{d}x}

Failed to parse (Conversion error. Server ("/media/api/rest_") reported: "Cannot get mml. TeX parse error: Double subscripts: use braces to clarify"): {\displaystyle p_{1}_{y}+=p_{1}_{d}y}