4/7 = 21/x-3 multiply the two sides by utilising x-3 (x-3) * 4/7 = 21 distribute (4x-12)/7 =21 4x - 12 = 147 4x = 159 x = 159/4 or 39.seventy 5 yet in any different case, turn each and each fraction over 7/4 = (x-3)/21 147/4 = x-3 147 / 4 = x - (12/4) 159/4 = x
Suppose you learn nothing else today remember that brackets MUST be used to present question correctly .As you have given it, question MUST be read as :-
4/7 + (21/x) - 3 and I am pretty sure that this is NOT what you mean ?