15 sqrt8/ sqrt18=15 2sqrt2/3sqrt2=30sqrt2/3sqrt2=10
√а+√в=√0,25+√36=0,5+6=6,5
Х+х-3+2х-3=55
4х-6=55
4х=55+6
4х=61
х=61:4
х=15 1/4=15.25
1)
у=2х-1
3х+2(2х-1)=12
3х+4х-2=12
7х=14
х=2
у=2×2-1=3
(2;3)
2)
4-4с+с^2-с^2-4с=4-8с=4-8×0.5=0
5)
у=3х-2
х^2-4х+8=3х-2
х^2-4х+8-3х+2=0
х^2-7х+10=0
д=49-4×10=9
х1=(7-3)/2=2
х2=(7+3)/2=5
у1=3×2-2=4
у2=3×5-2=13
(2;4)(5;13)