Answer:
5
Step-by-step explanation:
hello :
a + b = 9
...(*)
a - b = 6...(**)
add (*) and (**) : 2a =15.....(1)
subsct (**) and (*) : 2b=3 ....(2)
now divid (1) , (2) : 2a/2b = 15/3
means : a/b = 15/3 =5
Answer:
<em>3.36in</em>
Step-by-step explanation:
The total surface area of the cardboard is expressed as;
TSA = 2(LW + LH + WH)
L is the length = 4in
W is the width
H is the height = 7in
TSA = 130in²
Substitute the given values into the formula and get the width W
TSA = 2(LW + LH + WH)
130 = 2(4W+4(7) + 7W)
130 = 2(11W+28)
130 = 22W+56
22W = 130 - 56
22S = 74
W = 74/22
<em>W = 3.36in</em>
<em>hence the width of the photo is 3.36in</em>
something noteworthy is that the independent and squared variable in this case will be the "x", namely the graph of that quadratic is a vertical parabola.
![\bf f(x) = (x+2)(x-4)\implies 0=(x+2)(x-4)\implies x = \begin{cases} -2\\ 4 \end{cases} \\\\\\ \boxed{-2}\rule[0.35em]{7em}{0.25pt}0\rule[0.35em]{3em}{0.25pt}\stackrel{\downarrow }{1}\rule[0.35em]{10em}{0.25pt}\boxed{4}](https://tex.z-dn.net/?f=%5Cbf%20f%28x%29%20%3D%20%28x%2B2%29%28x-4%29%5Cimplies%200%3D%28x%2B2%29%28x-4%29%5Cimplies%20x%20%3D%20%5Cbegin%7Bcases%7D%20-2%5C%5C%204%20%5Cend%7Bcases%7D%20%5C%5C%5C%5C%5C%5C%20%5Cboxed%7B-2%7D%5Crule%5B0.35em%5D%7B7em%7D%7B0.25pt%7D0%5Crule%5B0.35em%5D%7B3em%7D%7B0.25pt%7D%5Cstackrel%7B%5Cdownarrow%20%7D%7B1%7D%5Crule%5B0.35em%5D%7B10em%7D%7B0.25pt%7D%5Cboxed%7B4%7D)
so the parabola has solutions at x = -2 and x = 4, and its vertex will be half-way between those two guys, namely at x = 1.
since this is a vertical parabola, its axis of symmetry, the line that splits its into twin sides, will be a vertical line, and it'll be the x-coordinate of the vertex, since the vertex hasa a coordinate of x = 1, then the axis of symmetry is the vertical line of x = 1.
Multiplying positive numbers always comes out positive, no matter how many there are. So you can forget about the positive ones.
Every two negative numbers in a multiplication produce a positive.
Another way to say that is: If the number of negative ones is EVEN,
the answer is positive, and if it's ODD, the answer is negative.
That monster product of eight numbers in problem #12 will be negative,
because there are an odd amount of negative factors in it.
