Solve the two simultaneous equations X2 +2Y2= 18 and X - Y = 3
1) X2 +2Y2= 182) X - Y = 3
Rearrange 2) in the form X=3-Y then substitute in to 1); (3-y)2+2Y2=18, this is your new equation 39+3Y+3Y+Y2+2Y2=183) 9+6y+3Y2= 18Divide equation 3) by 33 +2Y+Y2=6Solve for Y by equating to zero then factorising in to double brackets;Y2+2Y -3 = 0(Y+3)(Y-1)=0when (Y-1)=0, Y =1 and when (Y+3)=0, Y=-3solve x by substituting your found Y values in to equation 2when Y=1; X-1 = 3 so X=4When Y=-3; X--3=3, so X=0
RC
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