У = kx - 8
т. В ( - 2 ; - 18) ⇒ х = - 2 ; y = - 18
-18 = k * (-2) - 8
-18 = - 2k - 8
2k = - 8 + 18
2k = 10
k = 10 : 2
k = 5
Ответ : при k = 5 график функции у= kx - 8 проходит через т. В (-2; -18).
2y=3x-5. подставляем во 2 уравнение: 5x+2*(3x-5)=1; 5x+6x-10=1; 5x+6x=1+10; 11x=11; x=11/11=1. 2y=3*1-5, 2y= -2, y=(-2)/2= -1. Ответ: (1: -1).
Решите уравнение: 1)0,9х-0,6(х-3)=2(0,2х-1,3) 2)-0,4(3х-1)+8(0,8х-0,3)=5-(3.8х+4) 3)4/7(0,56-4,2у)+0,4=5/13(0,52-6,5у)
z18031973
1)0.9х-0.6х+1.8=0.4х-2.6
0.3х+1.8=0.4х-2.6
0.4х-0.3х=1.8+2.6
0.1х=4.4
х=4.4÷0.1
х=44
2)
-1.2х+0.4+6.4х-2.4=5-3.8х-4
5.2х-2=1-3.8х
5.2х+3.8х=1+2
9х=3
х=3÷9
х=1/3
3)
4/7(56/100-4 2/10у)+4/10=
=5/13(52/100-6 5/10у)
4/7(14/25-4 1/5у)+2/5=
=5/13(13/25-6 1/2у)
4/7(14/25-21/5у)+2/5=
=5/13(13/25-13/2у)
8/25-12/5у+2/5=1/5-5/2у
-12/5у+5/2у=1/5-8/25-2/5
-24/10у+25/10у=5/25-8/25-10/25
1/10у=-13/25
у=-13/25÷1/10
у=-13/25×10/1
у=-26/5=-5 1/5
2x - ay + bz
a = 3c
b = 14c^3
x = 5c^3 + 2
y = 6c^2 - c + 13
z = 5c - 1
2(5c^3 + 2) - 3c*(6c^2 - c + 13) + 14c^3*(5c - 1) =
= 10c^3 + 4 - 3c*6c^2 + 3c*c - 39c + 70c^4 - 14c^3 =
= 10c^3 + 4 - 18c^3 + 3c^2 - 39c + 70c^4 - 14c^3 =
= 70c^4 - 22c^3 + 3c^2 - 39c + 4