If r = 3s + 1 and t = s - 4, then what is r in terms of t?

r = 3s + 1

t = s - 4 ---------> s = t + 4 {added 4 to each side}

r = 3(t + 4) + 1 {substituted (t + 4), in for s, into top equation}

r = 3t + 12 + 1 {used distributive property}

t = s - 4 ---------> s = t + 4 {added 4 to each side}

r = 3(t + 4) + 1 {substituted (t + 4), in for s, into top equation}

r = 3t + 12 + 1 {used distributive property}

**r = 3t + 13**{combined like terms}*- Algebra House*