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
Answer:
-⅖
Step-by-step explanation:
We need to simplify the given equation and find out the value of a , as ,
=> 3(a-1)+31-11a = 4(2a+3)
=> 3a -3+31-11a = 8a + 12
=> -8a -28 = 8a + 12
=> 16a = -28-12
=> 16a = -40
=> a = -2/5
<h3>
• Hence the value of a is -⅖ .</h3>
Average speed = (1/2) (beginning speed + ending speed)
= (1/2) ( 13 m/s + 30 m/s )
= (1/2) ( 43 m/s )
= 21.5 m/s
Answer:
m∠ADC = 90°
5x-5 = 90
x = 19
Step-by-step explanation:
Answer:
D
Step-by-step explanation:
The slope = 4/2 = 2
and one point on the graph ( point B) is (5, 6) so point-slope equation is
y - 6 = 2(x - 5)
