If you have at least as many equations as your have unknown variables, the 'system' is solvable (unless the equations are copies of eachother).
In this case, isolate one letter and plug it in the other. I'm going for the 2a in the bottom one (it doesn't matter)
2a - 4b = 12 => (divide by two and move the b's to the other side)
a = 6 + 2b. (plug this one into the top equation)
4(6+2b) + 6b = 10 => 24+8b+6b = 10 => 24 + 14b = 10 => 14b = -14 => b=-1
a = 6 + -2 = 4.
So a=4 and b=-1.
F(x) = 2x - 1
subtitute x = 0 to the equation:
f(0) = 2· 0 -1 = 0 - 1 = -1
f(0) = -1
Answer:
$166.42.
Step-by-step explanation:
We have been given that the price of the cell phone is expected to increase by 165% in September 2015. The current price of a cell phone is $62.80.
The price of cell phone in September 2015 will be $62.80 plus 165% of $62.80.




Therefore, the predicted cost of a cell phone in September 2015 will be $166.42.
Isolate "x" onto one side:
5/3 * (6x+3) < 2x - 7
5(6x+3) < 3(2x-7)
30x + 15 < 6x - 21
24x < -36
x < -1.5