1) А.
А(-4;0) В(0;2)
(y-y₁)/(y₂-y₁)=(x-x₁)/(x₂-x₁) ⇒
(y-0)/(2-0)=(x-(-4))/(0-(-4)
y/2=(x+4)/4 |×4
2y=x+4
y=x/2+2
y=0,5x+2.
2) Б.
А(0;3) B(5;0)
(y-3)/(0-3)=(x-0)/(5-0)
(y-3)/(-3)=x/5 |×(-15)
5*(y-3)=-3x
5y-15=-3x
5y=15-3x |÷5
y=-0,6x+3.
2.
a. (0;3) (-2;-3)
(y-3)/(-3-3)=(x-0)/(-2-0)
(y-3)/(-6)=x/(-2) |×(-6)
y-3=3x
y=3x+3.
c. (4;0) (0;3)
(y-0)/(3-0)=(x-4)/(0-4)
y/3=(x-4)/(-4) |×12
4y=-3x+12 |÷4
y=-0,75x+3
d. (1;-1) (-1;1)
(y-(-1))/(1-(-1))=(x-1)/(-1-1)
(y+1)/2=(x-1)(-2) |×2
y+1=-x+1
y=-x
m. (-2;0) (-2;3)
(y-0)/(3-0)=(x-(-2))/(-2-(-2))
y/3=(x+2)/0 |×0
x+2=0
x=-2.
3.
5*3-1*9=15-9≡6
3*9-7*3=27-21≡6.
=(27c^-6)*(d^6)*(c/d)=(27c^-6)*c*(d^5)=(27c^-5)*d^5=27d^5/c^5
2√5=√2²*5=√4*5=√20
3√5=√3²*5=√9*5=√45
√14<√20<√45
√14<2√5<3√5
X+y=25 x×y=14 x=25-y y(25-y)=14 25y-y^=14