These problems are called systems of equations. Basically you have two linear equations and you need to find the values for x and y. In other words, all these equation are lines and our answer will be the exact point that the pair of lines intersect. For example, if we get x=1 and y=2 the lines will intersect at point (1,2). Now that you have some background knowledge here comes the tricks and tactics kid.
We know that we can solve one variable equation easily. For example...
x+1=2
x=1 obviously
Cause we have two variables x and y it is not possible to find a solution. For example, in the equation x+y=10, x=1 when y=9 and x=2 when y=8. There is not correct answer.
So what can we do? We have to make a two variable equation into a one variable equation.
There are two ways to do this: substitution and elimination. I will create a sample problem and then solve it using both methods.
x+y=2
2y-y=1
3)
-3x-5y=-7 -----> -12x-20y=-28
-4x-3y=-2 ------> -12x-9y=-6
-12x-20y=-28
-(-12x-9y=-6)
---------------------
-11y=-22
y=2
-3x-5(2)=-7
-3x=3
x=-1
4) 8x+4y=12 ---> 24x+12y=36
7x+3y=10 ---> 28x+12y=40
28x+12y=40
-(24x+12y=36)
---------------------
4x=4
x=1
8(1)+4y=12
4y=4
y=1
5) 4x+3y=-7
-2x-5y=7 ----> -4x-10y=14
4x+3y=-7
+(-4x-10y=14)
-------------------
-7y=7
y=-1
4x+3(-1)=-7
4x=-4
x=-1
6) 8x-3y=-9 ---> 32x-12y=-36
5x+4y=12 ---> 15x+12y=36
32x-12y=-36
+(15x+12y=36)
--------------------
47x=0
x=0
8(0)-3y=-9
-3y=-9
y=3
7)-3x+5y=-2
2x-2y=1 ---> x-y=1/2 ----> x=y+1/2
-3(y+1/2)+5y=-2
-3y-1.5+5y=-2
2y=-0.5
y=0.25
2x-2(0.25)=1
2x=1.5
x=0.75
Answer:
Step-by-step explanation:
Your exponential formula is in the form y = ab^x. In this form, the coefficient 'a' is the initial value, the y-intercept, the value when x=0. The value 'b' is the growth factor, which is 1 more than the growth rate per increment of x. This problem is asking for the growth rate to be expressed as a percentage.
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Given p(x) = 78500(1.02^x), we can compare to the exponential function form to see that ...
- a = 78,500
- b = 1.02 = 1 +0.02 = 1 +2%
The value of x is zero in the year 2000, so the population that year is ...
p(0) = a = 78,500
The increase per year is the value of 'b' with 1 subtracted:
growth rate = 2% per year
X/-9 ≥3 multiply both side by -9 to get rid of fraction
-9/1•x/-9 ≥-9•3
Cross cancel -9 on left side
x ≥ -27
Answer:
Jesse will have $120.
Step-by-step explanation:
First you need to set up your equation. We know Jesse has $60 already and that he charges $15 per lawn. Your equation will look something like this:
15x+60=?
Then you plug in the 4 lawns he did:
15(4)+60=
Then you solve and get 120! :)
PS Parenthesis mean you are multiplying. Same thing as saying
15 x 4 + 60= 120
Answer: d.1.66a
Step-by-step explanation:
