Solve the Fraction Division and Polynomial Subtraction: 49m/35n : 2n/7m - (2m²/n² - 4)

Question

49m35n:2n7m(2m2n24)=? \frac{49m}{35n}:\frac{2n}{7m}-(\frac{2m^2}{n^2}-4)=\text{?}

Video Solution

Solution Steps

00:00 Solve
00:03 Division is also multiplication by the reciprocal
00:12 Negative times positive is always negative
00:17 Negative times negative is always positive
00:23 Let's factor 35 into 7 and 5
00:27 Let's reduce what we can
00:44 Divide 49 by 10
00:51 Let's use the commutative law and arrange the exercise
00:54 And this is the solution to the question

Step-by-Step Solution

To solve this problem, let's go through it step-by-step:

  • Step 1: Simplify the division of fractions: 49m35n:2n7m \frac{49m}{35n}:\frac{2n}{7m}
  • Step 2: This is equivalent to multiplying: 49m35n×7m2n \frac{49m}{35n} \times \frac{7m}{2n}
  • Step 3: Simplify: Multiply numerators and denominators: 497m2352n2 \frac{49 \cdot 7 \cdot m^2}{35 \cdot 2 \cdot n^2}
  • Step 4: Compute simplification: 343m270n249m210n2 \frac{343m^2}{70n^2} \rightarrow \frac{49m^2}{10n^2}
  • Step 5: Substitute back to expression: 49m210n2(2m2n24) \frac{49m^2}{10n^2} - (\frac{2m^2}{n^2} - 4)
  • Step 6: Express 2m2n2\frac{2m^2}{n^2} in terms of 10 denominator: 20m210n2\frac{20m^2}{10n^2}
  • Step 7: Calculate complete subtraction: 49m210n220m210n2+4\frac{49m^2}{10n^2} - \frac{20m^2}{10n^2} + 4
  • Step 8: Simplify result: 29m210n2+4\frac{29m^2}{10n^2} + 4

Therefore, the solution to the problem is 2.9m2n2+4 2.9\frac{m^2}{n^2} + 4 .

Answer

2.9m2n2+4 2.9\frac{m^2}{n^2}+4