You want to eliminate one of the terms (x or y) in one of the equations so you can solve for the other variable. You have to multiply by the opposite number of the coefficient to be able to eliminate the term in the other equation. If the x coefficient is 2, then you have to multiply the entire other equation by -2. If the y coefficient is -5, then you have to multiply the entire other equation by 5.
10)
-4x + 9y= 9
x - 3y= -6
STEP 1:
multiply the bottom equation by 4
4(x- 3y)= 4(-6)
4x - 12y= -24
STEP 2:
add the top equation and the equation from step 2
-4x + 9y= 9
4x - 12y= -24
the x term cancels out
-3y= 15
divide both sides by -3
y= -5
STEP 2:
substitute the y value in either original equation to solve for x
x - 3y= -6
x - 3(-5)= -6
x + 15= -6
subtract 15 from both sides
x= -21
ANSWER: x= -21; y= -5
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12)
-7x + y= -19
-2x + 3y= -19
STEP 1:
multiply the top equation by -3 to eliminate the y term and to solve for x
-3(-7x + y)= -3(-19)
21x - 3y= 57
STEP 2:
add the bottom equation and the equation from step 2 to solve for x
-2x + 3y= -19
21x - 3y= 57
the y term cancels out
19x= 38
divide both sides by 19
x= 2
STEP 3:
substitute the x value in step 2 to solve for y; you can use either original equation
-7x + y= -19
-7(2) + y= -19
-14 + y= -19
add 14 to both sides
y= -5
ANSWER: x= 2; y=-5
Hope this helps! :)
Answer:
y = -3x + 4
Step-by-step explanation:
y = 4, this is where your line intersects with the y axis.
x = 1 is where your line is on the x axis (you want to include the part of the line that hits a point straight on, not one that goes past it.) So when it lands on the corner of the grids like the 4 for the y axis does, that is the point you are going to use.
Rise/Run is then your equation, so since you go down 3 and over 1 (counting from your y axis point), your slope is -3/1 or -3.
Then goes your y axis, so the final equation is
y= -3x + 4
I hope this helped!
1) Dimensions of rectangle are 14 and 7. Perimeter is:
2*(14+7) = 42.
2)Let the number of students who chose Tiger be x.
Number of students who chose Bulldog is 4*x.
Number of students who chose Lion is 2*x.
7x = 273 -> x=273/7=39.
Answer is 2*x=78.
3) The answer is B).
A and C aren't answers because they start with positive and end with negative numbers and D isn't answer because -6 1/4 is greater than -6,53.
