A small submarine started its dive at sea level and descended 30 feet per minute. Which integer represents the submarine's depth
2 answers:
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Answer:
Step-by-step explanation:
Let's organise our information :
- the function is (1/2)x²+2x+3
we want to khow the value of x that gives us : (1/2)x²+2x+3=x+7
Now the trick is to write this expression as a quadratic equation with zero at one side :
- (1/2)x²+2x+3=x+7
- (1/2)x²+2x+3-x-7=0
- (1/2)x²+x-4=0
Now let's solve this equation :
- a= 1/2
- b= 1
- c= -4
Δ=1²-4*(1/2)*(-4)
= 9
So we have two solutions :
- y= -4
- x= 2
So the solutions are -4 and 2