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
This is fairly simple
Plug in the numerical values given for each variable.
5(-2) -3(2) -(-3)
-10 -6 + 3 (negative x negative = positive)
-16 + 3
-13 is the final answer
Rent all
55.5/3 = 18.5
74/4 = 18.5
it costs 18.5 per day
1. y = 18.5 x where y =cost and x=days
A-1
10.99 per 1/2 day
10.99 * 2 =21.98 per day
2. it costs 21.98 per day from A-1
Rentall is the better deal because it is only 18.50 per day versus 21.98 per day
FALSE
metric system is known as the SI or sytem international system
it is used everywhere except for those few who cling to the english system (USA and UK)
The answer is -3/5y
alternative form is -0.6
