Solve -4(x²+5) = (-x+7)(4x-9)+5: Complete Quadratic Solution

Question

4(x2+5)=(x+7)(4x9)+5 -4(x^2+5)=(-x+7)(4x-9)+5

x=? x=?

Video Solution

Solution Steps

00:00 Solve
00:04 Open parentheses properly multiply by each factor:
00:12 Open parentheses properly multiply each factor by each factor:
00:37 Collect terms
00:44 We want to isolate the unknown X
00:49 Simplify what we can
01:01 Arrange the equation so that only X is on one side
01:13 Isolate the unknown X
01:24 And this is the solution to the question

Step-by-Step Solution

To solve this equation, we'll follow these steps:

  • Step 1: Expand and simplify the right-hand side.
  • Step 2: Set the equation to zero by moving all terms to one side.
  • Step 3: Simplify to obtain a standard quadratic equation.
  • Step 4: Use the quadratic formula to find the possible solutions for x x .

Now, let's work through each step:

Step 1:
Expand the right-hand side:
(x+7)(4x9)=x(4x)x(9)+7(4x)7(9)(-x + 7)(4x - 9) = -x(4x) - x(-9) + 7(4x) - 7(9)
= 4x2+9x+28x63-4x^2 + 9x + 28x - 63
Considering both sides: 4(x2+5)=4x2+9x+28x63+5 -4(x^2 + 5) = -4x^2 + 9x + 28x - 63 + 5 .

Step 2:
Simplify further by calculating:
4x220=4x2+37x58-4x^2 - 20 = -4x^2 + 37x - 58.

Step 3:
Move all terms to one side to achieve zero on the right-hand side:
4x220+4x237x+58=0-4x^2 - 20 + 4x^2 - 37x + 58 = 0
Simplifying, we get: 37x+38=037x + 38 = 0.

Step 4:
Since the x2 x^2 terms cancel, it's actually a linear equation:
37x=38 37x = -38 .
Solving for x x , we divide both sides by 37:
x=3837=1137 x = \frac{-38}{37} = -1\frac{1}{37} .

Therefore, the solution to the problem is x=1137 x = 1\frac{1}{37} .

Answer

1137 1\frac{1}{37}