Step-by-step explanation:
7x² + 9x² - x²
when you wrote the expression you used the "multiplication ×" and not "x".
anyway, when you have terms of the same variable of the same exponent, then the combination variable and exponent become an item. and the same items can simply be added in an expression.
this is similar to
7 apples + 9 apples - 1 apple
what would you do there ?
see ?
and the same we are doing now for the given expression : we are adding the terms up :
7x² + 9x² - x² = (7 + 9 - 1)x² = 15x²
and in the middle I gave you even the reason why we can do that.
please, let me know, if this is still unclear.
Answer: 180° i hope that this is one of the options
Answer:
y = -7, y = -3
Step-by-step explanation:
(y - 3)² = 2y² + 4y + 30
expand:
y² - 6y + 9 = 2y² + 4y + 30
subtract 30 from both sides
y² - 6y + 9 - 30= 2y² + 4y + 30 - 30
simplify:
y² - 6y - 21 = 2y² + 4y
subtract 4y from both sides
y² - 6y - 21 -4y = 2y² + 4y - 4y
simplify:
y² - 10y - 21 = 2y²
subtract 2y² from both sides
y² - 10y - 21 - 2y² = 2y² - 2y²
simplify:
-y² - 10y - 21 = 0
solve y by quadratic equation
- (-10) ± √ (-10² - 4(-1)(21)
y = --------------------------------------
2(-1)
y = -7, y = -3
