For these problems you have to use PEMDAS so for problem 15 you would do the parentheses first, (21-3) you get 18 and then exponents, 3^2, you get 9, no multiplication but there is division so take your answers, 18 and 9 and divide them, you get 2, so the answer to 15 is 2.
By using the Distributive Property, you would multiply 3 into the parenthesis (3 · x and 3 · -4)
3(x - 4) = 24
3x - 12 = 24
Then, you would solve like any normal one-step equation.
3x - 12 = 24
+12 +12
__________
3x 36
__ = __
3 3
x = 12, which is your final solution.
If you need any further explanations, please ask me :)
To factor this quadratic function, there are many ways that you can do this, the most common approach used to graph anything would be to make a table of values. Basically, make a chart with x coordinates on one side and y coordinates on the other side. Pick any values for your x coordinates and then find the correct y coordinate that results when you place that specific x coordinate into the function. After getting many points, plot those points on the grid and it should give you a parabola.
Another way to graph the function is to find the x intercepts, you can do this by setting the function to zero, and factoring the trinomial, using the appropriate method, then find the x intercepts
y = 2x^2 - 8x + 6
0 = (2x^2 - 6x - 2x + 6)
0 = 2x(x - 3) - 2(x - 3)
0 = (2x - 2)(x - 3).
Every hour is 15$, thus you can do x for hours, and the function would be 15x
