V = NRT/P (your statement)
V * P = NRT/P * P (multiply by P on both sides; to get NRT on its own)
VP = NRT (simplify)
VP/NR = NRT/NR (divide by NR on both sides; to get T on its own)
VP/NR = T (simplify)
T = VP/NR (exchange sides)
V * P = NRT/P * P (multiply by P on both sides; to get NRT on its own)
VP = NRT (simplify)
VP/NR = NRT/NR (divide by NR on both sides; to get T on its own)
VP/NR = T (simplify)
T = VP/NR (exchange sides)