√2+√32−3√18=x√8= √36×2+√16×2−3√2×9= x√2×4= 6√2+4√2−9√2=2×√2√2(6+4−9)=2x√2√2=2x√2 divide both sides by √2√2√2=2x√2√21 = 2x2x = 1x = 12