Answer:
$23.952, since money is always rounded up $23.96
Step-by-step explanation:
the first step is to get the total value of her purchases, thus we add 16.99 + 12.95 to get 29.94
since she will receive a 20% discount that means that she will be paying 80% of the total value
next we set up the ratio as follows:
portion paid / total = x/29.94 = 80/100
solving the ratio gives you 23.952
-x^2+105x-1050=1550
We move all terms to the left:
-x^2+105x-1050-(1550)=0
We add all the numbers together, and all the variables
-1x^2+105x-2600=0
a = -1; b = 105; c = -2600;
Δ = b2-4ac
Δ = 1052-4·(-1)·(-2600)
Δ = 625
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
<span><span>x1</span>=<span><span>−b−<span>Δ√</span></span><span>2a</span></span></span><span><span>x2</span>=<span><span>−b+<span>Δ√</span></span><span>2a</span></span></span>
<span><span>Δ<span>−−</span>√</span>=<span>625<span>−−−</span>√</span>=25</span>
<span><span>x1</span>=<span><span>−b−<span>Δ√</span></span><span>2a</span></span>=<span><span>−(105)−25</span><span>2∗−1</span></span>=<span><span>−130</span><span>−2</span></span>=+65</span>
<span><span><span>x2</span>=<span><span>−b+<span>Δ√</span></span><span>2a</span></span>=<span><span>−(105)+25</span><span>2∗−1</span></span>=<span><span>−80</span><span>−2</span></span>=+40</span></span>
Answer:
(5/6, 8/5)
Step-by-step explanation:
We multiply the second equation by 2, and then add the equations together.
12x+15y=34
-12x+10y=6
------------------
25y=40
We divide by 25 on both sides, and get that y = 8/5. We substitute y into either of the equations.
-6x +5(8/5)=3
Do the multiplication.
-6x+8=3
Subtract 8 from both sides.
-6x=-5
Divide by -6 on both sides.
x=5/6.
