⚠ 9x is read as the product 9*x: for a power, write 9^x Let's perform the differentiation: ddx(3 -9x) Apply the differentiation rule: ddx(f) = ddx(f)·12f with f = 3 -9x ddx(3 -9x)·12·3 -9x ℹddx(3 -9x)·12·3 -9x = ddx(3 -9x)2·3 -9x‖ddx(3 -9x) = 0 + ddx(-9x) 0 + ddx(-9x)2·3 -9x ▶Derivative: -92·3 -9x