noun
linear expression
Mathematical term for an expression of degree one, such as 2x + 3. Used in algebra contexts.
一次式のグラフは直線になります。
The graph of a linear expression becomes a straight line.
二次式 is a quadratic expression (degree two), whereas 一次式 is linear (degree one).
Compound of 一次 (linear, first-degree) and 式 (expression, formula). The reading is standard on'yomi.