Answer:
x=10
Step-by-step explanation:
Answer:
Step-by-step explanation:
Answer:
x = 3 and 7
There are two true solutions.
Step-by-step explanation:
To solve 
, use inverse operations by squaring both sides of the equal sign.
The quadratic expression can be factored into binomials and set equal to 0 by the zero product property to find x.
(x - 3) ( x - 7) = 0
x-3 = 0 so x=3
x-7 = 0 so x=7
Now check each solution into the original equation to be sure it solve the solution and is not extraneous.
and
![3-7 = \sqrt{-4(3)+28}\\[tex]-4 = \sqrt{16}\\-4 =-4](https://tex.z-dn.net/?f=3-7%20%3D%20%5Csqrt%7B-4%283%29%2B28%7D%5C%5C%5Btex%5D-4%20%3D%20%5Csqrt%7B16%7D%5C%5C-4%20%3D-4)
[/tex]
we know that
A relationship between two variables, x, and y, represent a proportional variation if it can be expressed in the form y=Kx
where
K is the constant of proportionality or slope of the linear equation
In this problem
x ----> is the number of months
y -----> is the total amount savings
we have the ordered pairs
(4,80) and (7,140)
so
Find the value of K
K=y/x
For (4,80)
K=80/4=20
For (7,140)
K=140/7=20
The value of K is the same for both ordered paits
that means------> is a proportional relationship
therefore
the linear equation is
y=20x
the answer is the option A, C and D
