This problem can be readily solved if we are familiar with the point-slope form of straight lines:
y-y0=m(x-x0) ...................................(1)
where
m=slope of line
(x0,y0) is a point through which the line passes.
We know that the line passes through A(3,-6), B(1,2)
All options have a slope of -4, so that should not be a problem. In fact, if we check the slope=(yb-ya)/(xb-xa), we do find that the slope m=-4.
So we can check which line passes through which point:
a. y+6=-4(x-3)
Rearrange to the form of equation (1) above,
y-(-6)=-4(x-3) means that line passes through A(3,-6) => ok
b. y-1=-4(x-2) means line passes through (2,1), which is neither A nor B
****** this equation is not the line passing through A & B *****
c. y=-4x+6 subtract 2 from both sides (to make the y-coordinate 2)
y-2 = -4x+4, rearrange
y-2 = -4(x-1)
which means that it passes through B(1,2), so ok
d. y-2=-4(x-1)
this is the same as the previous equation, so it passes through B(1,2),
this equation is ok.
Answer: the equation y-1=-4(x-2) does NOT pass through both A and B.
9514 1404 393
Answer:
- 6x +y = -6
- 6x -y = 8
- 5x +y = 13
Step-by-step explanation:
To rewrite these equations from point-slope form to standard form, you can do the following:
- eliminate parentheses
- subtract the x-term
- subtract the constant on the left
- if the coefficient of x is negative, multiply by -1
Of course, any operation you do must be done <em>to both sides of the equation</em>.
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1. y -6 = -6(x +2)
y -6 = -6x -12 . . . . . eliminate parentheses
6x +y -6 = -12 . . . . . add 6x
6x +y = -6 . . . . . . . . add 6
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2. y +2 = 6(x -1)
y +2 = 6x -6
-6x +y +2 = -6
-6x +y = -8
6x -y = 8 . . . . . . . . multiply by -1
__
3. y -3 = -5(x -2)
y -3 = -5x +10
5x +y -3 = 10
5x +y = 13
_____
<em>Additional comment</em>
The "standard form" of a linear equation is ax+by=c for integers a, b, c. The leading coefficient (generally, 'a') should be positive, and all coefficients should be mutually prime (have no common factors). That is why we multiply by -1 in problem 2.
<span>2 4/9 = 22/9
Area of square = a^2 = (22/9)^2 = 484/81 square inches.
hope that helps</span>
