X^2 + 4x – 7 = 0 Pls n thx
1 answer:
Answer:
x = - 2 ±
Step-by-step explanation:
To solve the equation using the method of completing the square.
Given
x² + 4x - 7 = 0 ( add 7 to both sides )
x² + 4x = 7
add ( half the coefficient of the x- term )² to both sides
x² + 2(2) x + 4 = 7 + 4
(x + 2)² = 11 ( take the square root of both sides )
x + 2 = ± ( subtract 2 from both sides )
x = - 2 ± ← exact solution
You might be interested in
Answer:
(3)
Replcaing equation (3) into equation (2) we got:
And solving for Y we got:
And solving for X from equation (3) we got:
So we need 3L of orange juice with 25% of concentration and 17 L of orange juice with 5% of concentration
Step-by-step explanation:
For this problem we can work with the concentration of water and orange juice.
Let X the amount for the orange juice with 25% content and Y the amount for the orange juice with 5% of content
Using the concentration of orange juice we have:
(1)
And for the water we have:
(2)
If we solve for X from equation (1) we got:
(3)
Replcaing equation (3) into equation (2) we got:
And solving for Y we got:
And solving for X from equation (3) we got:
So we need 3L of orange juice with 25% of concentration and 17 L of orange juice with 5% of concentration
We use the pithagorean formula: x^2 = 130^2 - 50^2 = 16900 -2500 = 14400;
then, x =
= 120 feet has the other dimension of the lot.
then, x =