Solve for x over the real numbers:
5 x^2 - 21 = 10 x
Subtract 10 x from both sides:
5 x^2 - 10 x - 21 = 0
Divide both sides by 5:
x^2 - 2 x - 21/5 = 0
Add 21/5 to both sides:
x^2 - 2 x = 21/5
Add 1 to both sides:
x^2 - 2 x + 1 = 26/5
Write the left hand side as a square:
(x - 1)^2 = 26/5
Take the square root of both sides:
x - 1 = sqrt(26/5) or x - 1 = -sqrt(26/5)
Add 1 to both sides:
x = 1 + sqrt(26/5) or x - 1 = -sqrt(26/5)
Add 1 to both sides:
Answer: x = 1 + sqrt(26/5) or x = 1 - sqrt(26/5)
Step-by-step explanation: The letter "x" is often used in algebra to mean a value that is not yet known. It is called a "variable" or sometimes an "unknown". In x + 2 = 7, x is a variable, but we can work out its value if we try!
Answer:
-10
Step-by-step explanation:
y= kx
or, k= y/x
or, k = 5/4
k = 1.25
y= kx = 1.25 × (-8) = -10
You would say one and seventy-five hundredths
Answer:
y=-3x+31
Step-by-step explanation:
y-y1=m(x-x1)
y-4=-3(x-9)
y-4=-3x+27
y=-3x+27+4
y=-3x+31
