Question

Решите уравнение 2)х^2=7х+18 3)х^2=-9х-8 4)х^2-20х=-5х+13х^2 5)х^2-6х=5х-12-х^2 6)х^2-7х=7х+16-х^2

Answer 1

2)x^2-7x-18=0
D=49+18*4=49+72=121
x1=(7+11)/2=9
x2=(7-11)/2=-2
3)x^2+9x+8=0
D=81-32=49
x1=(-9+7)/2=-1
x2=(-9-7)/2=-8
4)x^2-20x+5x-13x^2=0
14x^2-15x=0
x(14x-15)=0
x1=0;
14x-15=0
14x=15
x2=15/14
5)x^2-6x-5x+12+x^2=0
2x^2-11x+12=0
D=121-96=25
x1=(11+5)/4=4
x2=(11-5)/4=1.5
6)x^2-7x-7x-16+x^2=0
2x^2-14x-16=0
D=196+128=324
x1=(14+18)/4=8
x2=(14-18)/4=-1