The graph is y=x+4, to get the x-intercept we let y=0; and solve for x
thus we shall have:
0=x+4
subtract 4 from both sides
0-4=x+4-4
-4=x
hence the x-intercept will be at point (-4,0)
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:
<em>Terry had £780 initially and Faye had £1300</em>
Step-by-step explanation:
<u>System of Equations</u>
We'll call the following variables:
x = Terry's balance in his bank account
y = Faye's balance in her bank account
The initial relation between them is:
Cross-multiplying:
5x = 3y [1]
If Terry put £220 in his account he had x+220 and if Faye withdrew £300 from her account, she had y-300. Both quantities are equal, thus
x + 220 = y - 300
Subtracting 220:
x = y - 520 [2]
Substituting in [1]
5(y - 520) = 3y
Multiplying:
5y - 2600 = 3y
Adding 2600 and subtracting 3y:
2y = 2600
Dividing by 2:
y = 1300
From [2]:
x = 1300 - 520
x = 780
Terry had £780 initially and Faye had £1300
This is called the <u>Multiplication property of equality.</u>
The multiplication property of equality states that whatever you multiply on one side, you must multiply the same quantity on the other side of the equation. In this case, variable c is multiplied to both sides of the equation.
Answer:
second and third choice
Step-by-step explanation:
supplamentary = add up to be 180
