The missing number would be 28. 7*4=28.
The equation for this would be:
y+6= 1/5(x+7)
Speak in English please. I would be more pleased to help if you write in English.
This expression simplified is 3x-9. This is solved by combining like terms.
-x + 4x = 3x
-5 - 4 = -9
