Question

Розвʼяжіть рівняння:
1) 9× + 4 = 48 - 2x;
2) 9 - 7(× + 3) =5 - 6x;
3) (16y + 24)(2,8 - 0,7v)= 0.

Answer 1

Ответ:

1)

9x + 4 = 48 -2x

9x+2x=48-4

11x=44

x=4

2)

9-7(x+3)=5-6x

9-7x-21=5-6x

-7x+6x=5-9+21

-x=17 | *(-1)

x= -17

3)

(16y+24)(2,8-0,7y) =0

44,8y-11,2y²+67,2-16,8y = 0

28y-11,2y²+67,2 =0

-11,2y²+28y+67,2 =0 |*(-1)

11,2y²-28-67,2=0

a = 11,2 b=-28 c=-67,2

D=b²-4ac= (-28)²-4*11,2*(-67,2)= 3794,56

x1 = -b-√D/2a = 28-√3794,56/2*11,2 = -3/2 = 1 1/2 = 1,5

x2 = -b+√D/2a = 28+√3794,56/11,2= 4