Answer:
[tex] \displaystyle m_{1} = 2 \quad \text{and} \quad \displaystyle m _{2} = - 9[/tex]
Step-by-step explanation:
we are given a logarithm equation
[tex] \displaystyle \log_{4}( {m}^{2} ) = \log_{4}(18 - 7m) [/tex]
notice that, we have [tex]\log_4[/tex] both sides therefore we can get rid of it
[tex] \displaystyle {m}^{2} = 18 - 7m[/tex]
in order to solve it we should make it standard form we know that
[tex] \displaystyle a {x}^{2} + bx + c = 0[/tex]
so right hand side expression to left hand side and change its sign:
[tex] \displaystyle {m}^{2} + 7m- 18=0[/tex]
now we can solve it by using factoring method
to do so rewrite the middle term as sum or subtraction of two different terms
in that case -2m+9m is good to use
[tex] \displaystyle {m}^{2} - 2m + 9m - 18 = 0[/tex]
factor out m:
[tex] \displaystyle m({m}^{} - 2 )+ 9m - 18 = 0[/tex]
factor out 9:
[tex] \displaystyle m({m}^{} - 2 )+ 9(m - 2)= 0[/tex]
group:
[tex] \displaystyle (m - 2)(m + 9) = 0[/tex]
hence,
[tex] \displaystyle m_{1} = 2 \quad \text{and} \quad \displaystyle m _{2} = - 9[/tex]
remember that,
when we deal with logarithm equation we should always check the roots
let's check the root 1:
[tex] \displaystyle \log_{4}( {2}^{2} ) \stackrel{?}{=} \log_{4}(18 - 7.2) [/tex]
simplify square:
[tex] \displaystyle \log_{4}( 4) \stackrel{?}{=} \log_{4}(18 - 7.2) [/tex]
simplify multiplication:
[tex] \displaystyle \log_{4}( 4) \stackrel{?}{=} \log_{4}(18 - 14) [/tex]
simplify substraction:
[tex] \displaystyle \log_{4}( 4) \stackrel{?}{=} \log_{4}(4) [/tex]
simplify logarithm:
[tex] \displaystyle 1 \stackrel{ \checkmark}{=} 1[/tex]
let's check root 2:
[tex] \displaystyle \rm \log_{4}( { - 9}^{2} ) \stackrel{?}{=} \log_{4}(18 - 7.( - 9)) [/tex]
simplify square:
[tex] \displaystyle \rm \log_{4}( 81 ) \stackrel{?}{=} \log_{4}(18 + 63) [/tex]
simplify addition:
[tex] \displaystyle \rm \log_{4}( 81 ) \stackrel{ \checkmark}{=} \log_{4}(81) [/tex]
therefore,
[tex] \displaystyle m_{1} = 2 \quad \text{and} \quad \displaystyle m _{2} = - 9[/tex]
