Answer: 0.714286
turn 7/10 into .7 and divide normally
Answer:
1. no solutions
2. one solution
Step-by-step explanation:
1. -4(5-3x)=12x+20
-20+12x=12x+20
-40+12x=12x
-40=0?????
So no solutions.
2. 3x+7(x+1)=2(6x+5)+2
3x+7x+7=12x+10+2
10x+7=12x+12
-2x+7=12
-2x=5
x=-5/2
So one solution.
Answer:
4
Step-by-step
dam its so simple it hurts my brain
Hello,
y=2^(-x)
y=2^(2x)+3
==>2^(2x)+3=1/2^x
==>2^(3x)+3*2^x-1=0 (1)
Let's assume u=2^x
(1)==>u^3+3*u-1=0
which as 3 roots
u=0.322185354626 or
u = -0.161092677313 + i1.754380959784 or
u = -0.161092677313 - i1.754380959784.
Let's take the real solution
0.322185354626=2^x
==>x=ln(0.322185354626) / ln(2)
x=-1,6340371790199...
an other way is
f(x)=2^(3x)+3*2^x-1
f(-2)=1/64+3/4-1=-15/64 <0
f(-1)=1/8+1-1=1/8>0
==> there is a solution betheen -2<x<-1