Answer:
a = 9
Step-by-step explanation:
First we need to add (x^2+3x) to (3x^2+ax),
(x^2+3x)+(3x^2+ax)
Expand
= x^2+3x+3x^2+ax
Collect the like terms
= x^2+3x^2+3x+ax
= 4x^2 + 3x + ax
= 4x^2+(3+a)x
Equate the solution to 4x^2+12x
4x^2+(3+a)x = 4x^2+12x
Comparing the like terms on both sides
(3+a)x =12x
3 + a = 12
a = 12 - 3
a = 9
Hence the value of a is 9
Answer:
90
Step-by-step explanation:
(_ , _) means (X , Y)
(25 , ) means
X = 25 then you need find the value of Y from the equation .

so the first answer is (25,-3)
..............
( , -8) means
Y = -8 then you need to find the value of X from the equation .

so the second answer is ( 0 , -8 )
hope this would help you
Answer:
C) 4
Step-by-step explanation:
Replace the variable a with 4 to see if it makes the equation true.
4 + (-7) + 3 = -3 +3
-3 + 3 = 0; thererfore, the number 4 is the proper solution to the equation.
Answer:
Step-by-step explanation:
z-score representing 85% is 1.04 (from table)
Let x be the score representing the lower limit of 85%.
<u>Use the formula to find z-scores:</u>
<u>We have:</u>
<u>Substitute the values and solve for x:</u>
- 1.04 = (x - 78)/7
- x - 78 = 7.28
- x = 85.28
The lower limit of the top 15% is 85.28.
Since your score is greater than 85.28 you earned an A