The greatest common factor of 51 and 68 would be the largest positive integer that divides both of those numbers without a reminder. so that would be the GCF of 51&68.
Answer:
The temperature decreased by 9 °F in <u>6 days.</u>
Step-by-step explanation:
Let the number of days it takes for the temperature to decrease by 9 °F be 
.
Given:
Average daily temperature decreases by 
°F.
Decrease of temperature in 1 day = = 1.5 °F.
∴ Decrease in temperature in x days is 
.
Now, as per question, decrease in temperature in 'x' days is 9 °F.
Therefore, 
Therefore, the temperature decreased by 9 °F in 6 days.
Add the common factors which is x plus 2x plus 4x which is 7x so now you have the bx term rewritten to 7x+8
To factor a quadratic of the form ax^2+bx+c you need to find two values, j and k, that satisfy two conditions:
ac=jk and b=j+k in this case:
ac=jk=-18 and b=j+k=7 so j and k must be 9 and -2
Now replace bx with jx and kx in the original equation...
x^2-2x+9x-18 and factor the 1st and 2nd pair of terms...
x(x-2)+9(x-2) which is equal to
(x+9)(x-2)
