It is pretty easy to eliminate the wrong answers by trying the answers in the equations.
a. 7 times 30 is way more than 4
c. 6 times 226 is way more than 172, even after subtracting 64
d. 7 times -74 is way less than 4
The appropriate choice is
... b. x=4, y=30
You can check it with your graphing calculator.
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Since you have an expression for y, you can substitute that into the second equation:
... -2x + 6(2+7x) = 172 . . . . substitute for y
... 40x = 160 . . . . . . . . . . . . eliminate parentheses, subtract 12, collect terms
... x = 4 . . . . . . this is sufficient to help you locate the correct answer
Answer:
Step-by-step explanation:
The zero (root) of a function is any value of the variable that will produce an answer of zero. Graphically, the real zero of a function is where the graph of the function crosses the x-axis.
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f(x) = x³ + 3x² - x - 3
f(-3) = ( - 3 )³ + 3( - 3 )² - ( - 3 ) - 3 = 0
f(-1) = ( - 1 )³ + 3( - 1 )² - ( - 1 ) - 3 = 0
f(1) = ( 1 )² + 3( 1 )² - ( 1 ) - 3 = 0
