解方程:x^2-3x-4=0
(1)解:方程可化为(x-4)(x+1)=0,故可得方程的两个根:X1=4,X2=-1。
(2)解:方程可配方化为:(x-3/2)^2-25/4=0,
依完全平方差公式得:(x-3/2)^2-(5/2)^2=(x-3/2-5/2)(x-3/2+5/2)=0
即:(x-4)(x+1)=0,故可得方程的两个根:X1=4,X2=-1。
(1)x^2-9x+8=0 答案:x1=8 x2=1 (2)x^2+6x-27=0 答案:x1=3 x2=-9
(3)x^2-2x-80=0 答案:x1=-8 x2=10
(4)x^2+10x-200=0 答案:x1=-20 x2=10
(5)x^2-20x+96=0 答案:x1=12 x2=8
(6)x^2+23x+76=0 答案:x1=-19 x2=-4
(7)x^2-25x+154=0 答案:x1=14 x2=11
(8)x^2-12x-108=0 答案:x1=-6 x2=18
(9)x^2+4x-252=0 答案:x1=14 x2=-18
(10)x^2-11x-102=0 答案:x1=17 x2=-6
(11)x^2+15x-54=0 答案:x1=-18 x2=3
(12)x^2+11x+18=0 答案:x1=-2 x2=-9
(13)x^2-9x+20=0 答案:x1=4 x2=5
(14)x^2+19x+90=0 答案:x1=-10 x2=-9
(15)x^2-25x+156=0 答案:x1=13 x2=12
(16)x^2-22x+57=0 答案:x1=3 x2=19
(17)x^2-5x-176=0 答案:x1=16 x2=-11
(18)x^2-26x+133=0 答案:x1=7 x2=19
(19)x^2+10x-11=0 答案:x1=-11 x2=1
(20)x^2-3x-304=0 答案:x1=-16 x2=19
(21)x^2+13x-140=0 答案:x1=7 x2=-20
(22)x^2+13x-48=0 答案:x1=3 x2=-16
(23)x^2+5x-176=0 答案:x1=-16 x2=11
(24)x^2+28x+171=0 答案:x1=-9 x2=-19
(25)x^2+14x+45=0 答案:x1=-9 x2=-5
(26)x^2-9x-136=0 答案:x1=-8 x2=17
(27)x^2-15x-76=0 答案:x1=19 x2=-4
(28)x^2+23x+126=0 答案:x1=-9 x2=-14
(29)x^2+9x-70=0 答案:x1=-14 x2=5
(30)x^2-1x-56=0 答案:x1=8 x2=-7
(31)x^2+7x-60=0 答案:x1=5 x2=-12
(32)x^2+10x-39=0 答案:x1=-13 x2=3
(33)x^2+19x+34=0 答案:x1=-17 x2=-2
(34)x^2-6x-160=0 答案:x1=16 x2=-10
(35)x^2-6x-55=0 答案:x1=11 x2=-5
(36)x^2-7x-144=0 答案:x1=-9 x2=16
(37)x^2+20x+51=0 答案:x1=-3 x2=-17
(38)x^2-9x+14=0 答案:x1=2 x2=7
(39)x^2-29x+208=0 答案:x1=16 x2=13
(40)x^2+19x-20=0 答案:x1=-20 x2=1
(41)x^2-13x-48=0 答案:x1=16 x2=-3
(42)x^2+10x+24=0 答案:x1=-6 x2=-4
一元二次方程解题步骤,一起来看看吧
(1)x^2-9x+8=0 答案:x1=8 x2=1 (2)x^2+6x-27=0 答案:x1=3 x2=-9 (3)x^2-2x-80=0 答案:x1=-8 x2=10 (4)x^2+10x-200=0 答案:x1=-20 x2=10 (5)x^2-20x+96=0 答案:x1=12 x2=8 (6)x^2+23x+76=0 答案:x1=-19 x2=-4 (7)x^2-25x+154=0 答案:x1=14 x2=11 (8)x^2-12x-108=0 答案:x1=-6 x2=18 (9)x^2+4x-252=0 答案:x1=14 x2=-18 (10)x^2-11x-102=0 答案:x1=17 x2=-6 (11)x^2+15x-54=0 答案:x1=-18 x2=3 (12)x^2+11x+18=0 答案:x1=-2 x2=-9 (13)x^2-9x+20=0 答案:x1=4 x2=5 (14)x^2+19x+90=0 答案:x1=-10 x2=-9 (15)x^2-25x+156=0 答案:x1=13 x2=12 (16)x^2-22x+57=0 答案:x1=3 x2=19 (17)x^2-5x-176=0 答案:x1=16 x2=-11 (18)x^2-26x+133=0 答案:x1=7 x2=19 (19)x^2+10x-11=0 答案:x1=-11 x2=1 (20)x^2-3x-304=0 答案:x1=-16 x2=19 (21)x^2+13x-140=0 答案:x1=7 x2=-20 (22)x^2+13x-48=0 答案:x1=3 x2=-16 (23)x^2+5x-176=0 答案:x1=-16 x2=11 (24)x^2+28x+171=0 答案:x1=-9 x2=-19 (25)x^2+14x+45=0 答案:x1=-9 x2=-5 (26)x^2-9x-136=0 答案:x1=-8 x2=17 (27)x^2-15x-76=0 答案:x1=19 x2=-4 (28)x^2+23x+126=0 答案:x1=-9 x2=-14 (29)x^2+9x-70=0 答案:x1=-14 x2=5 (30)x^2-1x-56=0 答案:x1=8 x2=-7 (31)x^2+7x-60=0 答案:x1=5 x2=-12 (32)x^2+10x-39=0 答案:x1=-13 x2=3 (33)x^2+19x+34=0 答案:x1=-17 x2=-2 (34)x^2-6x-160=0 答案:x1=16 x2=-10 (35)x^2-6x-55=0 答案:x1=11 x2=-5 (36)x^2-7x-144=0 答案:x1=-9 x2=16 (37)x^2+20x+51=0 答案:x1=-3 x2=-17 (38)x^2-9x+14=0 答案:x1=2 x2=7 (39)x^2-29x+208=0 答案:x1=16 x2=13 (40)x^2+19x-20=0 答案:x1=-20 x2=1 (41)x^2-13x-48=0 答案:x1=16 x2=-3 (42)x^2+10x+24=0 答案:x1=-6 x2=-4
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