Answer:
two solutions : (-3;4) and (-5;6)
Step-by-step explanation:
hello :
X²+y²+18x+29=0 ..(1)
X+y=1 ...(2)
by (2) : y = 1 - x
put this value in (1) : x² +(1-x)² +18x+29 = 0
x² +1 +x² -2x+18x +29 =0
2x²+16x +30 = 0
x²+8x+15 =0
delta = b²-4ac a=1 b=8 c = 15
delta = (8)²-4(1)(15)=64-60 =4 = 2²
X1=(-8+2)/2 = - 3
X2=(-8-2)/2 = - 5
case 1 : x = -3 y = 1 - (-3) = 4
case 2 : x = -5 y = 1 - (-5) = 6
