Answer:
x1 = 0.64575
x2 = -4.64574
Step-by-step explanation:
Step 1: We want to rearrange the equation so all the variables are on one side
0 = -x² - 4x + 3
Step 2: We take out -1 in the first 2 terms so a = 1
0 = -(x² + 4x) + 3
Step 3: Force a square, take the 'b' value and divide it by 2 and square the result. Add it and subtract it from the inside of the brackets
b = 4
4/2 = 2
2² = 4
0 = -(x² + 4x + 4 - 4) + 3
Step 4: Move the -4 out remembering to apply the -
= -(x² + 4x + 4) + 4 + 3
Step 5: We notice is inside the brackets is a perfect square
0 = -(x + 2)² + 7
Therefore the vertex form of the equation is
y = -(x + 2)² + 7
Step 6: We want to solve the equation (find the x intercepts) so we set y to 0 and solve for x
0 = -(x + 2)² + 7
-7 = -(x + 2)²
7 = (x + 2)²
[tex] \sqrt{7 } = x + 2 [/tex]
[tex]x = \sqrt{7} - 2[/tex]
1st Solution:
x = +2.64575 - 2
x = 0.64575
2nd Solution:
x = -2.64575 - 2
x = -4.64574
