Sagot :
Bonjour,
(3x+7)²+(7x-3)² = (3x)²+2(3x)(7)+7²+((7x)²-2(7x)(3)+3²)
= 9x²+42x+49+49x²-42x+9
= 58x²+58
(x+2)²-(3x-5)² = x²+4x+4-(9x²-30x+25)
= -8x²+34x-21
(5x-7)²+(4x-8)(4x+8) = 25x²-70x+49+(16x²-64)
= 41x²-70x-15
Bonjour,
(3x+7)²+(7x-3)² = (3x)²+2(3x)(7)+7²+((7x)²-2(7x)(3)+3²)
= 9x²+42x+49+49x²-42x+9
= 58x²+58
(x+2)²-(3x-5)² = x²+4x+4-(9x²-30x+25)
= -8x²+34x-21
(5x-7)²+(4x-8)(4x+8) = 25x²-70x+49+(16x²-64)
= 41x²-70x-15