1.rút gọn: a,(2x+7)²-4)(x-5)(x+5) b,(x-2)mũ3-(x+3x+9)+6.(x-2)² 2.a,(3x-5)²-9(x-2)(x+2)=7 b,4x²-28x+49=25 c,(x+1)mũ 3 – (x-2)(x²+2x+4)
1.rút gọn: a,(2x+7)²-4)(x-5)(x+5) b,(x-2)mũ3-(x+3x+9)+6.(x-2)² 2.a,(3x-5)²-9(x-2)(x+2)=7 b,4x²-28x+49=25 c,(x+1)mũ 3 – (x-2)(x²+2x+4)-3(x²-2)=5