Step-by-step explanation:
18.029= (1×10)+(8×1)+(2×1100)+(9×1100)
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
____________________
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! :)
So the first one is 1 square meter of ceiling, and it says 1 square meter of cieling is 10.75. <em>So the first one is just that, 10.75</em>
The second one says 10 square meters, so just multiply 10.75, by 10.
In which case you get <em>107.5.</em> So that's the answer.
Third one, it gives you how many ceiling tiles you have. So you divide the 100 tiles by 10.75, which gives you 9.30232558, which becomes <em>9.3</em>
I'm sure you can figure out the last one.
Estimate 189 to the nearest tenth which would be 190. And then do the same for 643 which would be 640. 640-190= 450
I think it means like explain what are variable is. Only if your finding a variable: explain how you got the answer to that variable. Hope I helped!
