Question

Zad.1 Trzeba rozwiązać równanie :
5 ( x - 7 ) + 4 ( x + 2 ) = 0

Zad.2
- x + 5 ( x - 2 ) = 3 ( - 4 )
I sprawdzenie

Answer 1

Zad1
5 ( x - 7 ) + 4 ( x + 2 ) = 0
5x - 35 + 4x + 8 = 0
9x - 27 = 0
9x = 27 /:9
x = 3

Sprawdzenie
5(3-7)+4(3+2) = 0
5 × (-4) + 4 × 5 = 0
- 20 + 20 = 0
0 = 0

zad2
- x + 5 ( x - 2 ) = 3 ( - 4 )
- x + 5x - 10 = - 12
4x = - 12 + 10
4 x = - 2 /:4
x = - 0,5

Sprawdzenie:
-(-0,5) + 5 ( -0,5 - 2) = 3(-4)
0,5 + 5 × ( - 2,5) = -12
0,5 + 5 × (-2,5) = - 12
0,5 - 12,5 = -12
0,5 - 12,5 = - 12
- 12 = - 12

Answer 2

Zad1
5 ( x - 7 ) + 4 ( x + 2 ) = 0
5x - 35 + 4x + 8 = 0
9x - 27 = 0
9x = 27 /:9
x = 3

Sprawdzenie:
5(3-7)+4(3+2) = 0
5 × (-4) + 4 × 5 = 0
- 20 + 20 = 0
0 = 0

zad2
- x + 5 ( x - 2 ) = 3 ( - 4 )
- x + 5x - 10 = - 12
4x = - 12 + 10
4 x = - 2 /:4
x = - ½

Sprawdzenie:
-(-½) + 5 ( -½ - 2) = 3(-4)
½ + 5 × ( - 2½) = -12
½ + 5 × (-5/2) = - 12
½ - 25/2 = -12
½ - 12½ = - 12
- 12 = - 12

Answer 3

5 ( x - 7 ) + 4 ( x + 2 ) = 0
5x-35+4x+8=0
9x=27
x=3
5 ( 3 - 7 ) + 4 ( 3 + 2 ) = 0
-20+20=0
0=0

- x + 5 ( x - 2 ) = 3 ( - 4 )
-x+5x-10=-12
4x=-2
x=-0,5
- (-0,5) + 5 ( -0,5 - 2 ) = 3 ( - 4 )
0,5-2,5-10=-12
-12=-12