Paper 4, Section I, ENumbers and SetsPart IA, 2019Find all solutions to the simultaneous congruences4x≡1( mod 21) and 2x≡5( mod 45)4 x \equiv 1 \quad(\bmod 21) \quad \text { and } \quad 2 x \equiv 5 \quad(\bmod 45)4x≡1(mod21) and 2x≡5(mod45)