Answer:
1) 7 in
2) 11x=-7
3)2y - 7 + 3y = 5
4) i DONT'KNOWN
Step-by-step explanation:
1)
step 1
the length of the rectangle is 1 inch less than twice its width ( in other words , you have to subtract 1 to twice the width to get the length)
Let
L represents the length
W represent the width
Hence
Twice width= 2w
Now , replace
L=2w-1 equation (1)
Also
The perimeter =40 inches
[tex]perimeter= 2(L+W) 40=2(L+W) equation (2)[/tex]
Step 2
Solve for w
Replace equation (1) in equation (2)
[tex]40=2(L+W) equation (2)\\40=2((2W-1)+W)\\40=2(3W-1)\\40=6W-2\\Add 2 in both sides\\40+2=6W-2+2\\42=6W\\Divide both sides by 6\\\frac{42}{6}=\frac{6W}{6} \\7=W[/tex]
so ,the width is 7 in.
2) Given the equations
[tex]x+5y=3\\2x-y=-2[/tex]
The first step is to multiply the second equation by 5 (both sides of the equation)
[tex]5(2x-y=-2)\\5(2x-y)=5.(-2)\\5.2x-5.y=-10\\10x-5y=-10\\[/tex]
Next is to add both equations
x+5=3 +10x-5y=-10 = 11x+0y=-7
The result is 11x=-7
3)[tex]x+3y=5\\x+7=2y[/tex]
To make a substitution for x using the second equation in the first equation you :
1. solve for x the second equation
Subtract 7 in both sides of the equation:
[tex]x+7-7=2y-7\\x=2y-7\\[/tex]
2.Substitute the x in the first equation for the value of x you get in step 1 :
[tex]2y-7+3y=5[/tex]
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