Question

用配方法初三一元二次方程 4x的平方—3X=52

（1）4x平方—3X=52（2）5X平方=4—2X用配方法，一元二次方程

Answer 1

4x*x-3X=52 ==> (2x)*(2x)-2*(2x)*(3/4)+(3/4)*(3/4)=52+(3/4)*(3/4) ==> [(2x)-(3/4)]^2=52+(3/4)*(3/4) ==> (2x - 3/4)^2=52+9/16=841/16=(29/4)^2 ==> |2x - 3/4|= 29/4 ==> 2x - 3/4=±29/4 ==> x= -13/4, 45x*x=4-2x ==> 5x*x+2x=4 ==> x*x + (2/5)x= 4/5 ==>x*x+2*(1/5)*x+(1/5)*(1/5) =4/5+(1/5)*(1/5) ==> (x+1/5)^2=4/5 +1/25 ==> (x+1/5)^2=21/25 ==> x+1/5=±(√21)/5 ==> x= (-1±√21)/5

Answer 2

4分之14