10.
50+(2x)=20+(5x)
-20 -20
-2x -2x
30=3x
divide both sides by 3
10=x
Answer:
145
Step-by-step explanation:
angles in a pentagon add up to equal 540
Hence, 110 + 90 + 80 + 115 + v = 540
( note that we just created an equation that we can use to solve for v )
We now solve for v using the equation created
110 + 90 + 80 + 115 + v = 540
step 1 combine like terms
110 + 90 + 80 + 115 = 395
we now have 395 + v = 540
step 2 subtract 395 from each side
540 - 395 = 145
395 - 395 cancels out
we're left with v = 145
Answer:
Step-by-step explanation:
(x-3)²-4=0
(x-3)²=4=2²
x-3=±2
x=3±2
x=3-2,3+2
x=1,5
it has two distinct roots and a vertex at x=3
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.
