Answer:
[tex]\boxed{\sf a = 9 }[/tex]
Step-by-step explanation:
Two lines are given to us which are perpendicular to each other and we need to find out the value of a . The given equations are ,
[tex]\sf\longrightarrow 3x - 2y +7=0 [/tex]
[tex]\sf\longrightarrow 6x +ay -18 = 0 [/tex]
Step 1 : Convert the equations in slope intercept form of the line .
[tex]\sf\longrightarrow y = \dfrac{3x}{2} +\dfrac{ 7 }{2}[/tex]
and ,
[tex]\sf\longrightarrow y = -\dfrac{6x }{a}+\dfrac{18}{a} [/tex]
Step 2: Find the slope of the lines :-
Now we know that the product of slope of two perpendicular lines is -1. Therefore , from Slope Intercept Form of the line we can say that the slope of first line is ,
[tex]\sf\longrightarrow Slope_1 = \dfrac{3}{2} [/tex]
And the slope of the second line is ,
[tex]\sf\longrightarrow Slope_2 =\dfrac{-6}{a} [/tex]
Step 3: Multiply the slopes :-
[tex]\sf\longrightarrow \dfrac{3}{2}\times \dfrac{-6}{a}= -1 [/tex]
Multiply ,
[tex]\sf\longrightarrow \dfrac{-9}{a}= -1[/tex]
Multiply both sides by a ,
[tex]\sf\longrightarrow (-1)a = -9 [/tex]
Divide both sides by -1 ,
[tex]\sf\longrightarrow \boxed{\blue{\sf a = 9 }} [/tex]
Hence the value of a is 9 .
