Let x be the cost of 1 pen
then cost of 1 notebook = x + 8.20
Let y be the number of pens Tan buys
then number of notebooks Tan buys = y/4
She spent $26 more on books than on pens which means
Cost of notebooks - Cost of pens = 26
(x + 8.20) * y/4 - xy = 26
Sinplifying it
(xy + 8.20y)/4 - xy = 26
(xy + 8.20y - 4xy)/4 = 26
8.20y - 3xy = 104
She spent $394 which means
Cost of notebooks + Cost of pens = 394
(x + 8.20) * y/4 + xy = 394
Simplifying it
(xy + 8.20y)/4 + xy = 394
(xy + 8.20y + 4xy)/4 = 394
8.20y + 5xy = 1576
Now, we have two equations,
(1) 8.20y - 3xy = 104
(2) 8.20y + 5xy = 1576
Now we need to find a third equation with either x or y as the subject of any of both the previous equations.
Let's make y the subject of (2) equation
8.20y + 5xy = 1576
y(8.20 + 5X) = 1576
(3) y = 1576/(8.20 + 5x)
Let's substitute the new value of y from (3) into (1) because we rearranged (2) to from (3)
8.20y - 3xy = 104
y(8.20 - 3x) = 104
y = 104/(8.20 - 3x)
1576/(8.20 + 5x) = 104/(8.20 - 3x)
1576 * (8.20 - 3x) = 104 * (8.20 + 5x)
12923.2 - 4728x = 852.8 + 520x
12923.2 - 852.8 = 4728x + 520x
12070.4 = 5248x
12070.4/5248 = x
x = 2.3
Now find the value of y by substituting the value of x in either equation, preferably (3)
y = 1576/(8.20 + 5x)
y = 1576/(8.20 + 5 * (2.3))
y = 80
Therefore cost of 1 notebook = x + 8.20 = 2.3 + 8.20 = $10.50
|x-6| < 1 + 10 (move 10 to the right side)
|x-6| < 11
1)x-6 < 11 (here x >= 6)
2)-x+6 < 11 (here x < 6)
1)x<17
2)x>-5
so we get -5 < x < 17
the answer: (-5; 17)
3x²-y³ - y³ - z if x = 3, y = -2, z = -5
Simply plug in all the values :)
3(3²) - (-2³) - (-2³) - (-5)
Simplify.
3(9) + 2³ + 2³ + 5
Simplify.
27 + 8 + 8 + 5
Simplify.
35 + 13
Simplify.
48
~Hope I helped!~
Answer: Your answer should be C) 171! Hope this helps you!
Step-by-step explanation:
Hey there!
<u>Solve </u><u>the </u><u>equation</u><u>:</u>
c = 7 ✅
2c + 3 = 3c - 4
<em>></em><em>></em><em> </em><em>Subtract </em><em>3</em><em> </em><em>from </em><em>both </em><em>sides </em><em>:</em>
<em> </em>
2c + 3 - 3 = 3c - 4 - 3
2c = 3c - 7
<em>></em><em>></em><em> </em><em>Substrat </em><em>3</em><em>c</em><em> </em><em>from </em><em>both </em><em>sides </em><em>:</em>
2c - 3c = 3c - 7 - 3c
-c = -7
<em>></em><em>></em><em> </em><em>Divide</em><em> </em><em>each </em><em>side </em><em>by </em><em>-</em><em>1</em><em> </em><em>:</em>
-c / -1 = -7 / -1
c = 7
2c + 3 ⇔ 2(7) + 3 ⇔ 14 + 3 ⇔ 17
3c - 4 ⇔ 3(7) - 4 ⇔ 21 - 4 ⇔ 17
Therefore, your answer is c = 7 .
Mor about equation :
brainly.com/question/27353929
Have a good day :)
