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222-9+11+12:2*14+14 = ? ( )

Toán Lớp 9: phân tích đa thức thành nhân a> a- √a(a ≥0) b>3 √5-5 √3 c>x ²-3 d>a-b(a,b ≥0) e>a+b+2 √ab(a,b ≥0) f>a √a+b √b(a,b ≥0)

Toán Lớp 9: phân tích đa thức thành nhân
a> a- √a(a ≥0)
b>3 √5-5 √3
c>x ²-3
d>a-b(a,b ≥0)
e>a+b+2 √ab(a,b ≥0)
f>a √a+b √b(a,b ≥0)

Comments ( 2 )

  1. a)
    a – \sqrt{a} (a \ge 0)
    = \sqrt{a} (\sqrt{a} – 1)
    b)
    3 \sqrt{5} – 5 \sqrt{3}
    = \sqrt{3} . \sqrt{5} . (\sqrt{3} – \sqrt{5})
    =  \sqrt{15} . (\sqrt{3} – \sqrt{5})
    c)
    x^2 – 3
    = x^2 – (\sqrt{3})^2
    = (x – \sqrt{3})(x + \sqrt{3})
    d)
    a – b (a ; b \ge 0)
    = (\sqrt{a})^2 – (\sqrt{b})^2
    = (\sqrt{a} – \sqrt{b})(\sqrt{a} + \sqrt{b})
    e)
    a + b + 2 \sqrt{ab} (a ; b \ge 0)
    = (\sqrt{a})^2 + (\sqrt{b})^2 + 2 . \sqrt{a}.  \sqrt{b}
    = (\sqrt{a} + \sqrt{b})^2
    f)
    a \sqrt{a} + b \sqrt{b} (a ; b \ge 0)
    = (\sqrt{a})^3 + (\sqrt{b})^3
    = (\sqrt{a} + \sqrt{b}) [ (\sqrt{a})^2 + \sqrt{a} . \sqrt{b} + (\sqrt{b})^2]
    =  (\sqrt{a} + \sqrt{b})(a +  \sqrt{ab} + b)

  2. a) a – sqrta (age0) $\\$ = sqrta . sqrta – sqrta $\\$ =sqrta(sqrta-1) $\\$ b) 3sqrt5 – 5sqrt3 $\\$ = sqrt45 – sqrt75 $\\$ = sqrt15(sqrt3-sqrt5) $\\$ c) x^2 -3 $\\$ = x^2 – (sqrt3)^2 $\\$ = (x-sqrt3)(x+sqrt3) $\\$ d)a-b ( a,b ge0) $\\$ = (sqrta)^2 – (sqrtb)^2 $\\$= (sqrta-sqrtb)(sqrta+sqrtb) $\\$ e) a+b +2sqrt(ab ) (a,bge0) $\\$ = (sqrta)^2 +2sqrt(ab) + (sqrtb)^2 $\\$ = (sqrta+sqrtb)^2 $\\$ f) asqrta + bsqrtb (a,b ge0) $\\$ = (sqrta)^3 + (sqrtb)^3 $\\$= (sqrta+sqrtb)(a-sqrt(ab) +b)
     

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222-9+11+12:2*14+14 = ? ( )