(FACTORISATION) 1. 81(−6x−8)^2−25(2x−2)^2 2. (8x−7)^2+(5x+5)(24x−21) 3. 4(2x−8)^2−9(8x+7)^2 4. 49x^2−4 / 2 + 7x−2 / 8 5. 25/16(−5x+5)^2 − 49/4(8x−6)^2 Voilà mer
Mathématiques
Miiimi
Question
(FACTORISATION)
1. 81(−6x−8)^2−25(2x−2)^2
2. (8x−7)^2+(5x+5)(24x−21)
3. 4(2x−8)^2−9(8x+7)^2
4. 49x^2−4 / 2 + 7x−2 / 8
5. 25/16(−5x+5)^2 − 49/4(8x−6)^2
Voilà merci :)
1. 81(−6x−8)^2−25(2x−2)^2
2. (8x−7)^2+(5x+5)(24x−21)
3. 4(2x−8)^2−9(8x+7)^2
4. 49x^2−4 / 2 + 7x−2 / 8
5. 25/16(−5x+5)^2 − 49/4(8x−6)^2
Voilà merci :)
1 Réponse
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1. Réponse loulakar
Bonjour,
1. 81(−6x−8)^2−25(2x−2)^2
=(9(-6x-8))²-(5(2x-2))²
=(9(-6x-8)-(5(2x-2)) (9(-6x-8)+(5(2x-2))
=(-54x-72-10x+10)(-54x-72+10x-10)
=(-64x-62)(-44x-82)
2. (8x−7)²+(5x+5)3(8x−7)
=(8x-7) (8x-7+3(5x+5))
=(8x-7)(8x-7+15x+15)
=(8x-7)(23x+8)
3. 2²(2x−8)²−3²(8x+7)²
=(2(2x-8)-3(8x+7) (2(2x-8)+3(8x+7))
=(4x-16-24x-21) (4x-16+24x+21)
=(-20x-37) (28x+5)
4. (49x²−4) / 2 + (7x−2) / 8
=1/8(4(7²x²-4)+(7x-2))
=1/8 (4(7x-2)(7x+2)+7x-2)
=1/8 (7x-2) (4(7x+2)+1)
=(7x-2)/8 (28x+8+1)
=(7x-2)/8 (28x+9)
5. 25/16(−5x+5)²− 49/4(8x−6)²
=(5/4(-5x+5))²-(7/2(8x-6))²
=(5/4(-5x+5)-7/2(8x-6)) (5/4(-5x+5)+7/2(8x-6))
=(-25x/4+25/4-28x+21) (-25x/4+25/4+28x-21)
= (-25x/4 - 112x/4 + 25/4 + 84/4)(-25x/4 + 112x/4 + 25/4 - 84/4)
= (-137x/4 + 109/4)(87x/4 - 59/4)