Answer: Option C) Raj forgot the negative when substituting -15+9x for y.
Solution:
(1) 9x-y=15
(2) 2x+8y=28
Isolating y in the first equation. Subtracting 9x both sides of the equation:
(1) 9x-y-9x=15-9x
Subtracting:
(1) -y=15-9x
Multiplying both sides of the equation by -1:
(1) (-1)(-y)=(-1)(15-9x)
(1) y=-15+9x
Then Raj found the value of y. It's not option D.
Substitutng y by -15+9x in the second equation:
(2) 2x+8(-15+9x)=28
Then option C) is the answer: Raj forgot the negative when substituting -15+9x for y.
Eliminating the parentheses applying the distributive property in the multiplication:
(2) 2x-120+72x=28
Adding similar terms:
(2) 74x-120=28
Solving for x. Adding 120 both sides of the equation:
(2) 74x-120+120=28+120
Adding:
(2) 74x=148
Dividing both sides of the equation by 74:
(2) 74x/74=148/74
Dividing:
(2) x=2
Solving for y: Replacing x by 2 in the first equation:
(1) y=-15+9x
(1) y=-15+9(2)
Multiplying:
(1) y=-15+18
Subtracting:
(1) y=3
To find the range of data, you first order the data least to greatest:
7, 12, 15
Then you subtract the smallest number from the largest:
15-7=8
The range is 8.
The answer would be
D) 40
Answer:
<h3>
</h3>
Step-by-step explanation:
Let's solve:
As we know that the sum of angles of traingle adds to 180°
Collect like terms
⇒
⇒
⇒
Move constant to right hand side and change it's sign
⇒
Calculate the difference
⇒
Divide both sides of the equation by 6
⇒
Calculate
⇒
Now, let's replace the value:
⇒
⇒
⇒
Hope I helped!
Best regards!!
It should be 555^3=170953875