Answer: 3(x+9) = 12
Step-by-step explanation:
you can set up the equation as 3(x+9) = 12, since sum of x+9 multiply by 3 will equal 12, therefore you have that equation.
To solve for x:
3(x+9) = 12
x+9 = 4
x = -5
Answer:
Step-by-step explanation:
w=l-1
∵A=l×w
∴A=l×(l-1)
⇒42=l²-l
⇒l²-l-42=0 (After subtracting 42 from both sides)
Two factors of 42 that add to give negative 1 :-7+6
∴ (l-7)(l+6)=0
∴ l=7 or l=-6
but remember that length is a scalar quantity, hence l≠6 but l=7.
I hope this helped you solve this math problem and made you better understand
Answer:
Step-by-step explanation:
The system of equations (a) is the correct one for this situation. We must now solve this system for x and y, which are the unit costs.
Multiplying the 2nd equation by (-3/2) yields -12x - 18y = -168.
Now eliminate x by combining the two equations
12x + 5 y = 116
-12x -18y = - 168
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-13y = -52, or y = 4.
If y = 4 then 12x + 5y = 116, or
12x +5(4) = 116, or
12x + 20 = 116, or
12x = 96, or x = 8
Roller pens are $8/dozen and ball point pens are $4 per dozen.
