Answer:
Step-by-step explanation:
the first day he used 30 cups
the second day he used 15% of the remaining cups...a total of 90 cups were used on second day.
so 15%of the remaining cups = 90.....so if u let x be the total cups, then the remaining cups would be x - 30
15% of (x - 30) = 90.....turn ur percent to a decimal..." of " means multiply
0.15(x - 30) = 90
0.15x - 4.5 = 90
0.15x = 90 + 4.5
0.15x = 94.5
x = 94.5 / 0.15
x = 630 total cups <==
lets check..
start with 630 cups....used 30 the first day....leaving u with 600 cups....15% of the remaining cups = 90.....so 15% of 600 = 90....lets check it
15%of 600 = 0.15(600) = 90...yep, thats correct....there were 630 cups in the new un-opened box
2x^2 + 8x - 12 = 0..divide by 2
x^2 + 4x - 6 = 0
x^2 + 4x = 6...add 4 to both sides of the equation
x^2 + 4x + 4 = 6 + 4
(x + 2)^2 = 10....<== ur constant is 10
x + 2 = (+-)sqrt 10
x = -2 (+ - ) sqrt 10
x = -2 + sqrt 10
x = -2 - sqrt 10
Answer:
y=22
Step-by-step explanation:
y=-5(-2)+12
y=10+12
y=22
(4,10).
1. There are three ways to solve this: elimination, substitution, graphing.
2. I chose elimination, so I had to get one negative variable and one positive variable of the same value (for example, 18 and -18)
-7x+2y=-8
-16x+9y=26
I chose to get 2y and 9y to equal -18y and 18y.
So, multiply the first equation by -9. Multiply the second by 2.
63x-18y=72
-32x+18y=52
the 18s cross each other out. So you're left with
63x=72
-32x=52. Add them.
31x=124, divide both sides by 31, and you'll get 4.
x=4
Plug your answer for x into one of the equations. Let's use the first one.
-7(4)+2y=-8
-28+2y=-8. add 28 to both sides.
2y=20, divide both sides by 2.
y=10.
This makes your answer (4,10)
Answer:
ok
Step-by-step explanation:
