AB = AK + BK
AB = AK + ( AK - 4 )
36 = 2AK - 4
2AK = 40
AK = 20 ( cm )
BK = 20 - 4 = 16 ( cm )
Ответы без объяснений сойдут?
(x + 4) (x - 2) = x(2 - 3x) \\ x {}^{2} - 2x + 4x - 8 = 2x - 3x {}^{2} \\ 4x {}^{2} - 2x - 2x + 4x - 8 = 0 \\ 4x {}^{2} - 8 = 0 \\ x {}^{2} = 8 \div 4 \\ x {}^{2} = 2 \\ x = - + \sqrt{2}
(x+y)² = x²+2xy+y²
(x+y)² -2xy=x²+y²
(x+y)² -2*(-10)=29
(x+y)² +20=29
(x+y)² +20-29=0
(x+y)² - 9=0
(x+y)² - 3²=0
(x+y-3)(x+y+3)=0
1) x+y-3=0
x=3-y
(3-y)y= -10
3y-y²+10=0
y² -3y -10=0
D=(-3)² - 4*(-10)=9+40=49
y₁=(3-7)/2= -2 x₁*(-2)= -10
x₁=5
y₂=(3+7)/2=5 x₂*5= -10
x₂= -2
2) x+y+3=0
x= -3-y
(-3-y)y= -10
-3y-y² +10=0
y² +3y -10=0
D=3² -4*(-10)=9+40=49
y₁=(-3-7)/2= -5 x₁*(-5)= -10
x₁=2
y₂=(-3+7)/2=2 x₂*2= -10
x₂= -5
Ответ: (-5; 2); (-2; 5); (2; -5); (5; -2).