3^х-4=9
3^х=9+4
3^х=13
Х=log13 по основанию 3
5x-15y-26=2x+1;
-18y+4=9y+19;
3x-15y=27; (:3)
-27y=15; (:3)
x-5y=9;
-9y=5;
x-5y=9;
y=-0.5;
x-5(-0.5)=9;
y=-0.5;
x+2.5=9;
y=-0.5;
x=6.5;
y=-0.5.
1) 5x-3=7x+5
5x-3-7x=5
-2-3=5
-2x=3+5
-2x=8
x= -4
0.5x(-8x²+4x-14)= -4x³+2x²-7x