Solve 4(a-7)² = (2a-3)²: Finding the Value of a

Question

4(a7)2=(2a3)2 4(a-7)^2=(2a-3)^2

Find a

Video Solution

Solution Steps

00:00 Find A
00:04 We'll use the short multiplication formulas to open the parentheses
00:38 We'll solve the multiplications and squares
00:44 When there's a multiplication in a square, each factor is squared
00:54 We'll properly open parentheses and multiply by each factor
01:14 We'll reduce what we can
01:28 We'll isolate A
01:57 And this is the solution to the question

Step-by-Step Solution

To solve this problem, we will follow these steps:

  • Step 1: Expand both sides of the equation 4(a7)2=(2a3)24(a-7)^2 = (2a-3)^2.
  • Step 2: Simplify the resulting expressions.
  • Step 3: Solve for a a by equating the simplified expressions.

Now, let's work through each step:

Step 1: Expand both sides.
- Left-side expansion: 4(a7)2=4(a214a+49)=4a256a+196 4(a-7)^2 = 4(a^2 - 14a + 49) = 4a^2 - 56a + 196 .
- Right-side expansion: (2a3)2=(2a)22×2a×3+32=4a212a+9(2a-3)^2 = (2a)^2 - 2 \times 2a \times 3 + 3^2 = 4a^2 - 12a + 9.

Step 2: Set the expanded expressions equal to each other:
4a256a+196=4a212a+9 4a^2 - 56a + 196 = 4a^2 - 12a + 9 .

Now, subtract 4a2 4a^2 from both sides to simplify:
56a+196=12a+9-56a + 196 = -12a + 9 .

Simplify the equation by bringing all terms involving a a to one side and constant terms to the other side:
56a+12a=9196-56a + 12a = 9 - 196.
This simplifies to 44a=187 -44a = -187 .

Step 3: Solve for a a by dividing both sides by 44-44:
a=18744=414 a = \frac{187}{44} = 4\frac{1}{4} .

Therefore, the solution to the problem is a=414 a = 4\frac{1}{4} .

Answer

414 4\frac{1}{4}