Maths-
General
Easy

Question

Solve 2a – 3/b = 12 and 5a – 7/b = 1

Hint:

find 1/b by eliminating a and find a by substituting value of b  in the equations  .

The correct answer is: a = -81 ; b = -1/58


    Ans :- a = -81 ; b = -1/58
    Explanation :-
    table attributes columnalign right left right left right left right left right left right left columnspacing 0em 2em 0em 2em 0em 2em 0em 2em 0em 2em 0em end attributes row cell 2 a minus 3 divided by b equals 12 minus eq 1 end cell row cell 5 a minus 7 divided by b equals 1 minus eq 2 end cell end table
    Step 1:- find the value of 1/b by eliminating a
    By 5cross timeseq1 - 2cross timeseq2 we get
    5 left parenthesis 2 a minus 3 divided by b right parenthesis minus 2 left parenthesis 5 a minus 7 divided by b right parenthesis equals 5 left parenthesis 12 right parenthesis minus 2
    not stretchy rightwards double arrow 10 a minus 10 a minus 15 divided by b plus 14 divided by b equals 60 minus 2
    not stretchy rightwards double arrow negative 1 divided by b equals 58
     therefore space b space equals space minus 1 divided by 58
    Step 2:- find the value of a by substitution -1/b =  58 in eq 1
    2 a plus 3 left parenthesis negative 1 divided by b right parenthesis equals 12 not stretchy rightwards double arrow 2 a plus 3 left parenthesis 58 right parenthesis equals 12
    not stretchy rightwards double arrow 2 a equals negative 162

     therefore space a space equals space minus 81
    therefore a = -81 and b = -1/58 are the solution of the given equation.

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