Question

(x+1.4+x)(x+1.3)/2=1.53等于多少？

Answer 1

解：(x+1.4+x)(x+1.3)/2=1.53
（2x+1.4）（x+1.3）/2=1.53
2（x+0.7）（x+1.3）/2=1.53
（x+0.7）（x+1.3）=1.53
x²+0.7x+1.3x+0.91=1.53
x²+2x+0.91-1.53=0
x²+2x+1-0.09-1.53=0
（x+1）²=1.53+0.09
（x+1）²=1.62
（x+1）²=162/100
x+1=√162/10或者x+1=-√162/10
x=√162/10-1或者x=-√162/10-1

Answer 2

先适当的化简一下
(2x+1.4)(x+1.3)=3.06
2x^2+2.6x+1.4x+1.82=3.06
2x^2+4x+1.24=0
x^2+2x+0.62=0
x=(-2+-根号下1.52)/2

Answer 3

(x+0.7)(x+1.3)=1.53,
x^2+2x+0.91=1.53,
(x+1)^2=1.62,
x=-1土√1.62.

Answer 4

[2(x+0.7)(x+1.3)]/2=1.53
(x+0.7)(x+1.3)=1.53
x²+1.3x+0.7x+0.91=1.53
x²+2x=1.53－0.91
x²+2x+1=1.62
(x+1)²=162/100
x+1=±(9√2)/10
∴x=(-10±9√2)/10