Answer:No value of x
Step-by-step explanation:
Given
[tex]4^x+7(2^x)+12=0[/tex]
Let [tex]2^x=y[/tex]
[tex]y^2+7y+12=0[/tex]
[tex]y^2+3y+4y+12=0[/tex]
[tex]y(y+3)+4(y+3)=0[/tex]
[tex](y+3)(y+4)=0[/tex]
[tex]y=-3,-4[/tex]
[tex]2^x=-3[/tex]
or [tex]2^x=-4[/tex]
so there is no value of x for which [tex]2^x=-3 or -4[/tex]
because minimum value of [tex]^x=1[/tex]