13x+4
Combine like terms
If there is a minus sign count it as a negative
Answer:
Mr.Lin's present age is 30 years now. His son is 8 years old now.
Step-by-step explanation:
Let L = Mr.Lin's present age,
S = his son's present age.
First equation is
L + S = 38. (1)
The second equation is
L + 3 = 3*(S+3) (2) ("In three years' time, Mr.Lin will be three times as old as his son.")
From (1), express S = 38-L and substitute it into (2). You will get
L + 3 = 3*((38-L)+3), or
L + 3 = 114 - 3L + 9,
4L = 114 + 9 - 3,
4L = 120,
L = 30.
Answer:
(0,-5) and (-4,3)
Step-by-step explanation:
The given equations are
Make y the subject in the second equation;
Substitute into the first equation;
Expand:
When x=0,
This gives; (0,-5)
When x=-4
This gives (-4,3)
The answer for number 3 is 3.c
Put in a equality
20 > (70/x)
then you solve
20x > 70
x>70/20
x> 3.5 you can not put part of a chair in a row so you round up
****You can put 4 or more chairs in a row****
