Answer:
Heavenly, we need the forumula for the area of a triangle, do you know it?
Step-by-step explanation:
Area of a triangle is (1/2 ) * B*H
where B = base
H = height
then
A = 1/2* B * H
A is given to be 20
B = b
H = b+4
plug all those into the formula,
20 = (1/2)*b*(b+4)
use your algebra skillz :P
20 = 1/2 *(
+ 4b)
20*2 =
+ 4b
40 =
+ 4b
0 =
+ 4b-40
rewrite the above so it's in x format
+ 4x -40 = 0
use the quadratic formula to find x , and for our problem, remember that x represents the base, or b, but don't mix it up with the b in the quadatic fomula, with the b of the triangle, which is the base, they are differnt "b"s :P
X = (b±
) / 2*a
a = 1
b = 4
c = -40
x = (4±
) /2*1
x = ( 4±
) / 2
x = (4±
) / 2
x = (4±13.266499)/2
x= 2±6.633249
x = 2 + 6.633249 = 8.633
b= 8.633 cm
Answer:
-46
Step-by-step explanation:
5 (x - 2) - 14x. x=4
5 (4 - 2) - 14(4) (distribute)
20 - 10 - 14(4) (multiply)
20 - 10 - 56 (subtract and solve.)
10 - 56 = -46 - solution
hope this helps (:
Answer: A. ![\left[\begin{array}{ccc}29&13\\13&10\\\end{array}\right]](https://tex.z-dn.net/?f=%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7D29%2613%5C%5C13%2610%5C%5C%5Cend%7Barray%7D%5Cright%5D)
Step-by-step explanation:
The question is asking us to find the product of the matrices. The key difference is the second A has a little <em>T</em> in the exponent. This <em>T</em> means transpose. You multiply A by the transpose of A. To find the transpose, you turn the rows into columns.
![A^T=\left[\begin{array}{ccc}5&3\\2&-1\\\end{array}\right]](https://tex.z-dn.net/?f=A%5ET%3D%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7D5%263%5C%5C2%26-1%5C%5C%5Cend%7Barray%7D%5Cright%5D)
Now that we have our transpose, we can multiply the matrices.
![\left[\begin{array}{ccc}5&2\\3&-1\\\end{array}\right] \left[\begin{array}{ccc}5&3\\2&-1\\\end{array}\right] =\left[\begin{array}{ccc}5*5+2*2&5*3+2(-1)\\3*5+2(-1)&3*3+(-1)(-1)\\\end{array}\right] =\left[\begin{array}{ccc}29&13\\13&10\\\end{array}\right]](https://tex.z-dn.net/?f=%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7D5%262%5C%5C3%26-1%5C%5C%5Cend%7Barray%7D%5Cright%5D%20%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7D5%263%5C%5C2%26-1%5C%5C%5Cend%7Barray%7D%5Cright%5D%20%3D%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7D5%2A5%2B2%2A2%265%2A3%2B2%28-1%29%5C%5C3%2A5%2B2%28-1%29%263%2A3%2B%28-1%29%28-1%29%5C%5C%5Cend%7Barray%7D%5Cright%5D%20%3D%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7D29%2613%5C%5C13%2610%5C%5C%5Cend%7Barray%7D%5Cright%5D)