Answer:
18 = 3 x 6
Step-by-step explanation:
If you don't know the difference of the square of a number you can already see that it's telling 18 = 3 times that number so identify the missing number by multiplying 3 times a number.
18 = 3 x ?
18 = 3 x 6
18 = 18
:D
Answer:
6
Step-by-step explanation:
Let us start by writing an equation using the variable x.
The square of a number x minus 18 equals 3 times x:
[tex]x^{2} -18=3x[/tex]
Great! Now let us solve for x by moving the 3x term to the left side of the equation and obtain a quadratic equation:
[tex]x^{2} -3x-18=0[/tex]
We can use the quadratic formula [tex]\frac{-b±\sqrt{b^{2}-4ac } }{2a}[/tex] to solve for x. *Please ignore the A after b. I cannot remove it for some reason.*
From our equation, a represents the coefficient of the term with degree of 2. Therefore, our a variable is 1. b represents the coefficient of the term with degree 1. Out variable b is therefore -3. Lastly, c represents the term with degree 0. Our c variable is -18. Lets solve!
[tex]\frac{3 ±\sqrt{(-3)^{2}-4*1*(-18) } }{2*1} =\\\frac{3 ±\sqrt{9+72} }{2} =\\\frac{3 ±\sqrt{81} }{2} =\\\frac{3 ±9}{2} \\\\[/tex]
Now we have two possible solutions. Let us start with the addition version:
[tex]\frac{3+9}{2} =\\\frac{12}{2} =\\6[/tex]
Alternatively you could try the subtraction version:
[tex]\frac{3-9}{2} =\\\frac{-6}{2} =\\-12[/tex]
However, the question asks to find the positive solution. Therefore, out answer is 6.
I hope this helps! Please let me know if you have any questions :)
