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4. a varies directly as b, and a = 7
hen b= 2. Find b when a = 21.

plss solve this now ​


4 A Varies Directly As B And A 7hen B 2 Find B When A 21plss Solve This Now class=

Sagot :

4.

[tex]a = kb \\ \: \: \: \: 7 = k(2) \\ \: \: k = 3.5[/tex]

[tex] \: \: \: \: \: \: \: 21 = (3.5)b \\ \pink{\boxed{ b = 6}}[/tex]

5.

[tex] \: \: y = kx \\ \: \: \: \: \: \: \: 9 = k( \frac{3}{2} ) \\ k = 6[/tex]

[tex]y = (6)4 = \pink { \boxed{24}}[/tex]

6.

[tex] \: y = kx \\ - 4 = k(2) \\ k = - 2[/tex]

[tex] \: \: \: - 6 = ( - 2)x \\ \pink{\boxed{ x = 3} }\: \: \: \: \: [/tex]