Question

If u varies directly with v and u equals 6 when v equals negative 7 what is u when v equals 4

Answer 1

Step-by-step explanation:

$u \: directly \: v$

$u = k \: v$

$u = 6$

$v = - 7$

putting in upper equation to get value of k

$6 = - 7k$

$\frac { - 6}{ 7} = k$

u when v=4

$as \: u = kv$

$u = \frac{ - 6}{7} \times 4$

$u = \frac{ - 24}{7}$

Answer 2

Answer:

u = - $\frac{24}{7}$

Step-by-step explanation:

Given that u varies directly with v then the equation relating them is

u = kv ← k is the constant of variation

To find k use the condition u = 6 when v = - 7, thus

k = $\frac{u}{v}$ = $\frac{6}{-7}$ = - $\frac{6}{7}$

u = - $\frac{6}{7}$ v ← equation of variation

When v = 4, then

u = - $\frac{6}{7}$ × 4 = - $\frac{24}{7}$