Translate six less than seven times a number is equal to -20 into an equation
1 answer:
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Answer:
B
Step-by-step explanation:
+ 6 = x ( subtract 6 from both sides )
= x - 6 ( square both sides )
x = (x - 6)² ← expand using FOIL
x = x² - 12x + 36 ( subtract x from both sides )
0 = x² - 13x + 36 , that is
x² - 13x + 36 = 0 ← in standard form
(x - 4)(x - 9) = 0 ← in factored form
Equate each factor to zero and solve for x
x - 4 = 0 ⇒ x = 4
x - 9 = 0 ⇒ x = 9
As a check
Substitute these values into the equation and if both sides are equal then they are the solutions.
x = 4
left side = + 6 = 2 + 6 = 8
right side = x = 4
Since 8 ≠ 4 then x = 4 is an extraneous solution
x = 9
left side = + 6 = 3 + 6 = 9
right side = x = 9
Thus the solution is x = 9 → B
Step 1:
Here we have -3 in subtraction on the left side, so when we take it to the right we apply opposite operation of subtraction that is addition.
Step 2:
Next we have 4 in multiplication on left side, so dividing right side by 4,
Step 3:
taking log on both sides
Step 4:
Dividing right side by 2,
x= ln (3.75) /2 = 0.66088
Answer : x = 0.66088..
