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20 votes
20 votes
HII HELP PLEASE! I DONT UNDERSTAND​

HII HELP PLEASE! I DONT UNDERSTAND​-example-1
User Abdul Hannan Ijaz
by
2.8k points

2 Answers

13 votes
13 votes

Answer: C x = -2

Explanation:


3x^(2) - 30x - 72 = 0

[Add 72 on both sides]


3x^(2) - 30x = 72

[Factorise Left Hand Side of equation to get 3 on one side of a bracket]


3(x^(2) -10x) = 72

[Divide each side by 3 to just get the brackets and the x's on one side]


x^(2) -10x = 24

[Minus 24 on both side as the equation must = 0]


x^(2) -10x-24=0

[Solve the square on the left hand side]


(x-12)(x+2)=0

[Solve for x on left hand side - two possible answers]


x-12=0 \\ x=12


x+2=0\\x=-2

[The answer '12' is not in the option for the question so '-2' is the answer]

User BST Kaal
by
2.7k points
11 votes
11 votes

Answer:

C

Explanation:

3x^2-30x=72

3(x^2-10x)=72

x^2-10x=24

Then do the subtitules

Answer:C

Give me brainlliest

User Friggle
by
2.9k points