X= time in hour.
Eric’s equation
30x+50
Albert’s equation
20x+80
30x+50=20x+80
10x=30
X=3
3 hours.
You can solve a system of equations 3 ways.
1. Elimination
This method is eliminates one of the variables in the system of equations to get 1 equation with only one 1 variable.
2. Graph
You graph both of the equations and find where they intersect if at all.
3. Substitution
If you know the value of one of variables, you can substitute it back into the equation.
Answer:
Given: Consider a triangle ABC in which AD is median drawn from vertex A.
To prove: AB + AC > AD
Proof: In Δ A B D
AB + B D> AD ⇒[In a triangle sum of lengths of two sides is greater than the third side] .................(1)
In Δ A CD
AC + DC > AD [In a triangle sum of lengths of two sides is greater than the third side] .................(2)
Adding (1) and (2)
AB + AC+ B D + D C > B D + DC
A B+ A C+ B C > 2 B D .................(3)
Also , Considering Δ AB C
AB + B C > B C ⇒[In a triangle sum of lengths of two sides is greater than the third side]
⇒ AB + B C - B C >0 ........................(4)
Adding (3) and (4)
A B+ B C+B C+ AB +A C- B C > 2 A D
⇒2 AB + 2 A C> 2 A D
Dividing both side of inequality by 2, we get
A B+ A C> A D
Hence proved.
Answer:
7.5
Step-by-step explanation:
1) You can start off by dividing 30 by 4
30/4
2) You should get 7.5