-5x+4y=11
substitute for x which is 5
(-5)(5)+4y=11

simplify :
4y-25=11

add 25 on both sides
4y-25=11
+25 +25
the 25 cancels out

so it would be 4y=36
and you divide both sides by 4

4/4 =36/4

which gives you (5,9)
x= 5 , y =9

6 0

3 years ago

Given that f(x) = x + 3<br> a) Find f(2)

Nataly_w [17]

${ \qquad\qquad\huge\underline{{\sf Answer}}}$

Here we go ~

In the above question, it is given that :

$\qquad \sf \boxed{ \sf f(x) = \frac{x + 3}{2} }$

A.) Find f(2) :

$\qquad \sf \dashrightarrow \: f(2) = \dfrac{2 + 3}{2}$

$\qquad \sf \dashrightarrow \: f(2) = \dfrac{5}{2}$

$\qquad \sf \dashrightarrow \: f(2) = 0.5$

B.) Find ${ \sf {f}^{-1}(x) }$ :

$\qquad \sf \dashrightarrow \: let \: y = f (x)$

so, we can write it as :

$\qquad \sf \dashrightarrow \: y = \dfrac{x + 3}{2}$

$\qquad \sf \dashrightarrow \: 2y = x + 3$

$\qquad \sf \dashrightarrow \: x = 2y - 3$

Now, put x = ${ \sf {f}^{-1}(x) }$ , and y = x and we will get our required inverse function ~

$\qquad \sf \dashrightarrow \: f {}^{ - 1}(x) = 2x- 3$

C.) Find ${ \sf {f}^{-1}(12) }$ :

$\qquad \sf \dashrightarrow \: f {}^{ - 1}(12) = 2(12)- 3$

$\qquad \sf \dashrightarrow \: f {}^{ - 1}(12) = 36- 3$

$\qquad \sf \dashrightarrow \: f {}^{ - 1}(12) = 33$

7 0

1 year ago