From situations to linear equations

Before you start Find the change from 3 to 9 and from 2 to 5. The changes are 6 and 3, so the ratio is 2. Keep the same subtraction order for both changes. Domain and range (A.2(A)) Domain lists allowed inputs; range lists resulting outputs. A ticket count is discrete while elapsed time can be continuous. A graph of y=3x+2 may allow all real inputs mathematically, but a story can restrict it. Equivalent line equations (A.2(B)) Calculate m=(y₂−y₁)/(x₂−x₁). Point-slope form y−y₁=m(x−x₁) preserves the known point. Expand into y=mx+b or rearrange into Ax+By=C without changing the line.