It is 9.5
that is your answer
Put 6 into f(x). 2(6)-8 = 4
Put that 4 into g(x)
4-5 =-1
-1
I love these. It's often called the Shoelace Formula. It actually works for the area of any 2D polygon.
We can derive it by first imagining our triangle in the first quadrant, one vertex at the origin, one at (a,b), one at (c,d), with (0,0),(a,b),(c,d) in counterclockwise order.
Our triangle is inscribed in the 
rectangle. There are three right triangles in that rectangle that aren't part of our triangle. When we subtract the area of the right triangles from the area of the rectangle we're left with the area S of our triangle.
That's the cross product in the purest form. When we're away from the origin, a arbitrary triangle with vertices 
will have the same area as one whose vertex C is translated to the origin.
We set 
That's a perfectly useful formula right there. But it's usually multiplied out:
That's the usual form, the sum of cross products. Let's line up our numbers to make it easier.
(1, 2), (3, 4), (−7, 7)
(−7, 7),(1, 2), (3, 4),
[tex]A = \frac 1 2 ( 1(7)-2(-7) + 3(2)-4(1) + -7(4) - (7)(3)
His room was 115.62 per night and he stayed 3 nights so that is
115.62 * 3 = 346.86
his flight was 45.70 + 32.49 there and home so
45.70 + 32.49 = 78.19
15.00 a day on food for 4 days is
15.00 * 4 = 60
she won 75 and lost 15 so
75 - 15 = 60
add them up
346.86 + 78.19 + 60 + 60 = 545.05
Answer:
<h2>30</h2>
Step-by-step explanation:
<h3>to understand the steps</h3><h3>you need to know about:</h3>
- system of linear equation
- word problems
- PEMDAS
first step
let's create the equation word problem
<h3>my mother's current age is four times the sum of the ages of my two sisters. After 5 years, my mother's age will be double the sum of the ages of my two sisters. What is the current age of my mother? (imaginary problem)</h3>
let's solve
let my mother's and sister's age be x and y respectively
according to the first condition,x=4y....(I)
according to the 2nd condition,x+5=2(y+5×2).....(ii)
so the system of linear equations is
x=4y
x+5=2(y+5×2)
gets from the second equation
x+5=2(y+10)
x+5=2y+20
4y+5=2y+20 (as x=4y)
2y=15
y=7.5
so the age of mother is
x=4.(7.5)
x=30
