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
complette the square to get vertex form or y=a(x-h)^2+k
(h,k) is vertex
1. group x terms, so for y=ax^2+bx+c, do y=(ax^2+bx)+c
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2, factor out the leading coefinet (constant in front of the x^2 term), basicallly factor out a
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3. take 1/2 of the linear coefient (number in
front of the x), and square it ,then add negative and positive of it
inside parnthases
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4. complete the squre and expand
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so
y=-1/4x^2+4x-19
group
y=(-1/4x^2+4x)-19
undistribute -1/4
y=-1/4(x^2-16x)-19
take 1/2 of -16 and squer it to get 64 then add neg and pos inside
y=-1/4(x^2-16x+64-64)-19
factorperfect square
y=-1/4((x-8)^2-64)-19
expand
y=-1/4(x-8)^2+16-19
y=-1/4(x-8)^2-3
vertex is (8,-3)
Answer:
75
Step-by-step explanation:
x= 75
been that the line is perpendicular (the two lines that intersect in such a way that they have a right angle, or a 90 degree angle, between them)
Answer:
x= -1 and 0
Step-by-step explanation:
