whats the equation of this x(x+10)=39
I know X = 3, but I simply just saw that in front of me, i dont know how to make an equation out of it.
What you need to do is expand the brackets:
x(x+10)= 39
First mutiply each term in the brackets by x. so x times x = x^2. Then x times 10 = 10x.
Now your equation is x^2+10x = 39
You'll find that when you substitute 3 into your equation, it will equal 39.
Solve for x:
x (x+10) = 39
Expand out terms of the left hand side:
x^2+10 x = 39
Add 25 to both sides:
x^2+10 x+25 = 64
Write the left hand side as a square:
(x+5)^2 = 64
Take the square root of both sides:
x+5 = 8 or x+5 = -8
Subtract 5 from both sides:
x = 3 or x+5 = -8
Subtract 5 from both sides:
Answer: | x = 3 or x = -13
