Answer: x = -4 or x = 7
Step-by-step explanation:
x^2 - 3x - 28 =/>
(factor)
(x^2 + 4)(x-7) = 0
x + 4 = 0 or x - 7 = 0
(subtract -4 from 0 and 7 from 0)
x = -4 or x =7
Sifa needs to earn $244
Solution
400-156=244
Therefore, He needs to earn $244 more before his trip.
Answer:
81
Step-by-step explanation:
the formula for an arithmetic sequence:
aₙ = a₁ + (n-1)d
where aₙ = the nth term
a₁ = the 1st term = -3
n = the term number = 13
d = the common difference = 7
Plugging in those values into the formula to find a₁₃:
a₁₃ = -3 + (13-1)7
= -3 + (12)7
= -3 + 84
= 81
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.
