Question

4a+9b/5a-b если 3a+5b=0

Answer 1

3a + 5b = 0

5b = - 3a

b = - 0,6a

$\frac{4a+9b}{5a-b}=\frac{4a+9*(-0,6a)}{5a-(-0,6a)}=\frac{4a-5,4a}{5a+0,6a}=\frac{-1,4a}{5,6a}=-0,25$

Answer 2

Смотри во вложениииии

Answer 3

To find the value of the expression $\frac{4a+9b}{5a-b}$ given that $3a+5b=0$, we first need to solve the system of equations formed by the two expressions:

1. $3a + 5b = 0$ (given condition)
2. $\frac{4a+9b}{5a-b}$ (expression to evaluate)

We can start by solving the first equation for one of the variables in terms of the other:

$3a + 5b = 0$

Subtract $3a$ from both sides:

$5b = -3a$

Now, divide both sides by 5:

$b = -\frac{3a}{5}$

Now that we have $b$ in terms of $a$, we can substitute this expression into the second equation:

$\frac{4a + 9\left(-\frac{3a}{5}\right)}{5a - \left(-\frac{3a}{5}\right)}$

Simplify the expression step by step:

Step 1: Calculate $9\left(-\frac{3a}{5}\right)$

$9\left(-\frac{3a}{5}\right) = -\frac{27a}{5}$

Step 2: Calculate $5a - \left(-\frac{3a}{5}\right)$

$5a - \left(-\frac{3a}{5}\right) = 5a + \frac{3a}{5} = \frac{25a}{5} + \frac{3a}{5} = \frac{28a}{5}$

Step 3: Substitute the simplified expressions back into the main expression:

$\frac{4a - \frac{27a}{5}}{\frac{28a}{5}}$

Step 4: Find a common denominator for the terms in the numerator:

$\frac{4a - \frac{27a}{5}}{\frac{28a}{5}} = \frac{\frac{20a}{5} - \frac{27a}{5}}{\frac{28a}{5}} = \frac{\frac{-7a}{5}}{\frac{28a}{5}}$

Step 5: Invert the denominator and multiply:

$\frac{\frac{-7a}{5}}{\frac{28a}{5}} = \frac{-7a}{5} \times \frac{5}{28a}$

Step 6: Cancel out common terms:

$\frac{-7a}{5} \times \frac{5}{28a} = \frac{-7}{28}$

So, the value of the expression $\frac{4a + 9b}{5a - b}$ when $3a + 5b = 0$ is $\frac{-7}{28}$.