1)x^2-15x+26=0
D=(-15)^2 - 4*1*26=121
х1=(15+11)/2=26/2=13
х2=(15-11)/2=4/2=2
2)4у^2+3у-7=0
D=3^2 - 4*4*(-7)=121
у1= (-3+11)/4*2=8/8=1
у2= (-3-11)/4*2= -14/8= -7/4
17+33=50
18+32+50... 24+26=50 (50х8+25)х6 = 2550
7,8х+9,1у²-х+1,9у²-8,7у²
6,8х+2,3у²
х : (х + 3) = 8/3
х = 8/3 * (х + 3)
х = 8/3х + 8
х - 2 2/3х = 8
-1 2/3х = 8
х = 8 : ( - 5/3)
х = 8/1 * (- 3/5) = - 24/5 = - 4 4/5 = - 4,8