Answer: D
Step-by-step explanation:
Consider the first equation. Subtract 3x from both sides.
y−3x=−2
Consider the second equation. Subtract x from both sides.
y−2−x=0
Add 2 to both sides. Anything plus zero gives itself.
y−x=2
To solve a pair of equations using substitution, first solve one of the equations for one of the variables. Then substitute the result for that variable in the other equation.
y−3x=−2,y−x=2
Choose one of the equations and solve it for y by isolating y on the left hand side of the equal sign.
y−3x=−2
Add 3x to both sides of the equation.
y=3x−2
Substitute 3x−2 for y in the other equation, y−x=2.
3x−2−x=2
Add 3x to −x.
2x−2=2
Add 2 to both sides of the equation.
2x=4
Divide both sides by 2.
x=2
Substitute 2 for x in y=3x−2. Because the resulting equation contains only one variable, you can solve for y directly.
y=3×2−2
Multiply 3 times 2.
y=6−2
Add −2 to 6.
y=4
The system is now solved.
y=4,x=2
It is not necessary that the function decreasing over a given interval always be negative.
A function f(x) (value) decreases as x increases.
This does not mean that value of f(x) is negative.
It can have positive number as range.
3(x-5)-4(x+3)
Multiply the first bracket by 3
(3)(x)=3x
(3)(-5)=-15
(-4)(x)=-4x
(-4)(3)=-12
3x-15-4x-12
3x-4x-15-12 ( combine like terms)
Answer: -x-27
If AB + BC = AC, and A, B and C are collinear, then
B is between A and C
There are three unknowns in this problem. First, let's assign variables for these unknowns.
Let
x be the amount received by the first friend
y be the amount received by the second friend
z be the amount received by the third friend
Next, we formulate equations for the relationships
x = 4z
z = 4y
x + y + z = <span>$231,000
Solving simultaneously,
4(4y) + y + 4y = </span><span>$231,000
21y = </span><span>$231,000
y = $11,000
z = 4($11,000) = $44,000
x = 4($44,000) = $176,000</span>
