Answer:
x=-1
Step-by-step explanation:
By adding the bottom lines you can get
2x+11 = x+10
Simplifying this gets you
x=-1
Let x be the mass of the paperbacks and y be the mass of the textbook.
20x + 9y = 44.4 ----------- (1)
25x + 10y = 51 -------------(2)
(1) x 10:
200x + 90y = 444 --------(1a)
(2) x 9:
225x + 90y = 459 --------(2a)
(2a) - (1a):
25x = 15
x = 0.6 -------- sub into (1)
20 (0.6) + 9y = 44.4
12 + 9y = 44.4
9y = 44.4 - 12
9y = 32.4
y = 3.6
So the paperback's mass is 0.6 pounds and textbook is 3.6 pounds
Answer:
(x - 7) • (5x - 7)
Step-by-step explanation:
18 + 81 = 9(x²<span> + 6x + 9)
</span><span>11 = (x + 3)</span>²
When we are completing the square, we are going to move the value of c across the equals. We will do that by adding, and end up with
18=9(x²+6x)
We take the value of b (the coefficient of x), divide it by 2 and square it:
(6/2)²=3²=9
This is the value that completes the square. However, since the entire square is multiplied by 9, this value must be multiplied by 9 before we can add it across the equals:
18+9(9) = 9(x²+6x+9)
18+81=9(x²+6x+9)
99=9(x²+6x+9)
Dividing both sides by 9, we have:
11=x²+6x+9
11=(x+3)²
If you round 13.245 seconds to the nearest tenth, the answer is 13.2 seconds.
Hope this helped!
