Question

已知一元二次方程x的平方减2x加m等于0，若方程的两个实数根为x1，X2，且x1加3x等于3，求m的值

Answer 1

x^2-2x+m=0, x1+x2=2,x1x2=m，x1+3x2=3， x1+x1+2x2=3, 2+2x2=3, x2=1/2,x1=2-x1=3/2, m=x1x2=3/4

Answer 2

x1 + x2 = 2 x1 + 3x2 = 3 ==> (x1 +x2) + 2x2 = 3 ==> 2 + 2x2 = 3 ==> x2 = 1/2 x^2 - 2x + m = 0 ==> (1/2)^2 - 2 * (1/2) + m = 0 ==> 1/4 - 1 + m = 0 ==> m = 3/4