For which (k) will (y=260-(k-4)x) show linear decay?

Correct answer: \(k>4\)

In the linear form \(y=mx+c\), \(m\) is the slope. Here, the coefficient of \(x\) is \(-(k-4)=4-k\). For decay, the slope must be negative, so \(4-k<0\), which gives \(k>4\). At \(k=4\), the slope is zero, so the value remains constant rather than decaying. Exam tip: check the sign of the coefficient of \(x\) to identify linear growth or decay.