Answer:
x=18 y=69
Step-by-step explanation:
3x+5y=399
x+5y=363
2x=36
x=18
18+5y=363
5y=345
y=69
Answer:
3x-2y=6
Step-by-step explanation:
Subtract 3x from both sides of the equation
Divide each term by −2 and simplify.
y=-3+
Rewrite in slope-intercept form
y=
Use the slope-intercept form to find the slope and y-intercept.
Find the values of m and b using the form y=mx+b


The slope of the line is the value of m, and the y-intercept is the value of b.
Slope: 
y-intercept: -3
Any line can be graphed using two points. Select two x values, and plug them into the equation to find the corresponding y values.
Choose 0 to substitute in for x to find the ordered pair.
(0,−3)
Choose 1 to substitute in for x to find the ordered pair.

Graph the line using the slope and the y-intercept, or the points.
slope:
y-intercept:-3
Function 1:
f(x) = -x² + 8(x-15)f(x) = -x² <span>+ 8x - 120
Function 2:
</span>f(x) = -x² + 4x+1
Taking derivative will find the highest point of the parabola, since the slope of the parabola at its maximum is 0, and the derivative will allow us to find that.
Function 1 derivative: -2x + 8 ⇒ -2x + 8 = 0 ⇒ - 2x = -8 ⇒ x = -8/-2 = 4
Function 2 derivative: -2x+4 ⇒ -2x + 4 = 0 ⇒ -2x = -4 ⇒ x = -4/-2 ⇒ x= 2
Function 1: f(x) = -x² <span>+ 8x - 120 ; x = 4
f(4) = -4</span>² + 8(4) - 120 = 16 + 32 - 120 = -72
<span>
Function 2: </span>f(x) = -x²<span> + 4x+1 ; x = 2
</span>f(2) = -2² + 4(2) + 1 = 4 + 8 + 1 = 13
Function 2 has the larger maximum.