Step-by-step explanation:
the error:
it is stated that
subtract (5x)/(x+7) from both sides
multiply both sides by x + 7
7(x+7) = 49x
7x + 49 = 49x
subtract 7x from both sides to isolate x and its coefficient
49 = 42x
thus, this is only true when 49 = 42x. in order for these two equations to be equal, they must <em>always </em>be true, so this is wrong
the solution:
we want to express 7/x as (something) / (x+7). to do this, we can multiply 7/x by 1.
anything divided by itself = 1. thus, if we multiply both the numerator and the denominator by something that turns x into (x+7), we can do what we want to do.
(x+7)/x * x turns x into (x+7), so we multiply both the numerator and denominator by (x+7)/x to get
substitute this for 7/x in our original problem
Answer:
30
Step-by-step explanation:
Answer:
c
Step-by-step explanation:
because i said so
Answer:
You will need to use simultaneous equations.
Method:
First we need to make one set of variable the same, in this case we will:
-Multiply the top equation by 3 to get 6x
-Multiply the bottom equation by 2 to get 6x
The result will be as follows:
1) 2x+5y=-13 x3
1) 6x+15y=-39
2) 3x-4y=-8 x2
2) 6x-8y=-16
Now we will make both equations equal to 6x:
1) 6x=-15y-39
2) 6x=8y-16
Now because they both equal 6x, they therefore equal each other:
-15y-39=8y-16
-23=23y
y=-1
Now that we have y, we can substitute it back into one of the equations to get x:
1) 2x+5(-1)=-13
2x-5=-13
2x=-8
x=-4
f(x)=3x^2 and g(x)=4x^3+1
(f*g)(x) = (3x^2)(4x^3 + 1)
(f*g)(x) = 12x^5 + 3x^2
The term with highest degree is the first term 12x^5, so the degree of the product is 5.
Answer: C. 5