Given the equation y = 3x + 2 , what is the value of y when x = 3?
2 answers:
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Let Jean's speed while running = x mph
Then Jean's speed while riding will be = x+9 mph
Distance covered by running = 8 miles
Distance covered by riding = 11 miles
Total time taken to complete the race = 1.5 hours
As,
So, time for running=
And time for riding=
Equation becomes:
Now, multiply every term by 2x(x+9) to clear denominators:
Simplifying it we get
Solve the quadratic equation using formula
putting a=3 , b= -11, c= -144
we get (x - 9)(3x + 16) = 0
where x=9 and x=
Neglect the negative answer as speed cannot be negative, so x = 9 mph
Hence, Jean's running speed is 9 mph and riding speed is x+9 = 9+9 = 18 mph
We check with each options
'Or' represents the intersection of two graphs
'And' represents two separate graphs'
We have two separate shaded part in the given graph
So we ignore the options that has 'and' in between
LEts check first and second option
Simplify the first part and second part
multiply both sides by 2 .
x < 2 or 4x - 2 > = 26
solve 4x-2 > = 26
add 2 on both sides and then divide both sides by 4
4x >= 28
x >= 7
So solution is x<2 or x>=7 . that is the graph on number line
Lets check with second option
3x-3<3 or 2x+8>=22
add 3 on both sides
3x < 6
divide both sides by 3
so x< 2
2x+8>=22
subtract 8 on both sides
2x >= 30
divide both sides by 2
x >= 15
x<2 or x>=15 that does not satisfies the graph
So option A is correct