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
a) 1,000 + 0 + 40 + 9
b) 40,000 + 3,000 + 800 + 70 + 0
c) 8,000,000 + 100,000 + 5
ANSWER
EXPLANATION
The area of the two tra-pezoidal faces
The area of the 5 by 6.4 rectangular face
The area of the two square faces
The area of the 9 by 5 rectangular face is
The surface area of the design is:
Answer:
Step-by-step explanation:
4/5 x - 2 > 3/10 * 2x
4/5 x - 2 > 3/5 x
4/5 x - 2 - 3/5x> 0
1/5x > 2
x > 10
