Question

I need help figuring out a way to find x for both

Answer 1

Both problems are proportions, so cross multiply in each problem to get rid of the fractions.

41. $\dfrac{9}{x} = \dfrac{12}{21}$

Reduce the fraction in the right side.

$\dfrac{9}{x} = \dfrac{4}{7}$

Cross multiply.

$4x = 9 \times 7$

$4x = 63$

$x = \dfrac{63}{4}$

$x = 15.75$

43. $\dfrac{5}{2} = \dfrac{10}{x - 2}$

Cross multiply.

$5(x - 2) = 2 \times 10$

$5x - 10 = 20$

$5x = 30$

$x = 6$