1)
5х+6=12.5х
12.5х-5х=6
7.5х=6
х=6÷7.5
х=0.8
2)
12-8х+24=6+4х
36-8х=6+4х
4х+8х=36-6
12х=30
х=30÷12
х=2.5
=4/2³+8/2²+5/2¹=4/8+8/4+5/2=0,5+2+2.5=5.
Система:
3x+2y=240
6x=275
x=275/6
Система:
x=275/6
3×275/6+2y=240
275×2+2y=240
275+y=120
y=-155
Ответ:x=275/6; y=-155
X²+13x+36=0
D=13²-4*1*36=25=5²
x1=(-13+5)/2=-4
x2=(-13-5)/2=-9