中学3年数学 平方根 根号を含む式の計算 3確認問題1・解答
1、次の計算をしてください。
?,√18ー√8ー3√2
=√9×2ー√2×4ー3√2
=3√2ー2√2ー3√2
=ー2√2
答え ー2√2
?,√12ー2√75+√48
=√4×3ー2√25×3+√16×3
=2√3ー2×5√3+4√3
=2√3ー10√3+4√3
=ー4√3
答え ー4√3
?,2√45+√5ー√500
=2√5×9+√5ー√5×100
=2×3√5+√5ー10√5
=6√5+√5ー10√5
=ー3√5
答え ー3√5
?,3√2+√6/√3ー2√8
=3√2+√6×√3/√3×√3ー2√2×4
=3√2+√18/3ー2×2√2
=3√2+√2×9/3ー4√2
=3√2+3√2/3ー4√2
=3√2+√2ー4√2
=0
答え 0
?,√18/3ー4√2+4√10/√20
=√2×9/3ー4√2+4√10×√20/√20×√20
=3√2/3ー4√2+4√200/20
=√2ー4√2+4√2×100/20
=√2ー4√2+4×10√2/20
=√2ー4√2+40√2/20
=√2ー4√2+2√2
=ー√2
答え ー√2
?,√18/3ー6/√8ー2√2ー√1/2
=√2×9/3ー6√8/√8×√8ー2√2ー√1×√2/√2×√2
=3√2/3ー6√2×4/8ー2√2ー√2/2
=√2ー6×2√2/8ー2√2ー√2/2
=√2ー12√2/8ー2√2ー√2/2
=√2ー3√2/2ー2√2ー√2/2
=2√2/2ー3√2/2ー4√2/2ー√2/2
=ー6√2/2
=ー3√2
答え ー3√2
?,5√3×√24ー8/√2
=5√3×√4×6ー8√2/√2×√2
=5√3×2√6ー8√2/2
=5×2√3×6ー4√2
=10√18ー4√2
=10√2×9ー4√2
=10×3√2ー4√2
=30√2ー4√2
=26√2
答え 26√2
?,6√2×4/√3ー2√24
=6√2×4√3/√3×√3ー2√4×6
=6√2×4√3/3ー2×2√6
=6×4√2×√3/3ー4√6
=24√6/3ー4√6
=8√6ー4√6
=4√6
答え 4√6
?,1/√18ー1/√6÷√12
=1×√18/√18×√18ー1×√6/√6×√6×1/√12
=√18/18ー√6/6×1×√12/√12×√12
=√2×9/18ー√6/6×√12/12
=3√2/18ー√6/6×√3×4/12
=√2/6ー√6/6×2√3/12
=√2/6ー√6/6×√3/6
=√2/6ー√6×√3/6×6
=√2/6ー√18/36
=√2/6ー√2×9/36
=√2/6ー3√2/36
=√2/6ー√2/12
=2√2/12ー√2/12
=√2/12
答え √2/12
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