Question

Help us plazz this is mathematics IGCSE fast as you can​

Answer 1

Explanation:

y varies direcrtly with √(x+5) wich can be expressed mathematically as:

● y = k*√(x+5)

Let's calculate k khowing that y=4 and x=-1

● 4 = k*√(-1+5)

● 4 = k*√(4)

● 4 = k * 2

● k = 4/2

● k = 2

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Let's calculate y khowing that x = 11

● y = k*√(x+5)

● y = 2×√(11+5)

● y = 2× √(16)

● y = 2× 4

● y = 8

Answer 2

The value of y is 8.

Explanation:

Given that y is directly proportional to √(x+5) so the equation is y = k√(x+5) where k is constant. First, you have to find the value of k with given values :

`y = k √(x + 5)`

`let \: x = - 1,y = 4`

`4 = k √( - 1 + 5)`

`4 = k √(4)`

`4 = k(2)`

`4 / 2 = k`

`k = 2`

So the equation is y = 2√(x+5). In order to find the value of y, you have to substitute x = 11 into the equation :

`y = 2 √(x + 5)`

`let \: x = 11`

`y = 2 √(11 + 5)`

`y = 2 √(16)`

`y = 2(4)`

`y = 8`