x^2+5x-1/6=x^2+x+1/6
移項(xiàng)x^2-x^2+5x-x=1/6+1/6
合并同類項(xiàng)得4x=1/3
系數(shù)化為一得x=1/12
(2)2ab/(a+b)(a+c)+2bc/(a-b)(c-a)
有點(diǎn)難度
解原式=2ab(a-b)(a-c)/(a+b)(a+c)(a-b)(a-c)+2bc(a+b)(a+c)/(a-b)(c-a)(a+b)(a+c)
=2ab(a-b)(a-c)/(a+b)(a-b)(a+c)(a-c)-2bc(a+b)+(a+c)/(a-b)(a+b)(a-c)(a+c)后面變符號(hào)因?yàn)槲野?c-a)變?yōu)?a-c)了使分母相同
同分母相加 =2ab(a-b)(a-c)-2bc(a+b)(a+c)/(a^2-b^2)(a^2-c^2)
=2ab(a^2-ab-ac+bc)-2bc(a^2+ab+ac+bc)/(a^2-b^2)(a^2-c^2)
=2ba^3-2a^2b^2-2a^c+2b^2c-2bca^2-2ab^2c-2abc^2-2b^2-c^2/ (a^2-b^2)(a^2-c^2)
看暈了.
祝愉快