He would have to work 13 hours
12 * .25= 3 engines. 12 *.50= 6 engines. She added 3 more engines.
Answer:
b) −3y2−2x+1
d) −4xy+4y2−y−10
Step-by-step explanation:
b) -4x <u>+ y2</u> <em>- 9</em> <em>+ 10</em> - x + 3x<u> - 4y2</u>
<u>(i have just underlined, italic and made it bold to show the like terms)</u>
-4x - x + 3x = -2x
y2 - 4y2 = -3y2
-9 + 10 = 1
-2x - 3y2 + 1
d) 0 - 20 <u>- 5xy</u> + 4y2 + 10 - y <u>+ xy</u>
<u>(i have just underlined, italic and made it bold to show the like terms, however the '-y' and '4y2' have no like terms)</u>
0 - 20 + 10 = - 10
-5xy + xy = - 4xy
-10-4xy+4y2-y
y varies directly with x.
The constant of variation is k = 7
Step-by-step explanation:
We have to check whether both vary directly with each other or not.
Every pair of x and y will be considered one by one
If y varies directly with x, it should satisfy y = kx or k = yx
So,
For x= -2, y=-14

For
x=3, y=21

For
x=5, y=35

As k is same for all pairs of x and y, it can be concluded that:
y varies directly with x.
The constant of variation is k = 7
Keywords: Proportion, variation
Learn more about proportion at:
#LearnwithBrainly