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Solving Equations Using Addition and Subtraction (3.1). A.4f Apply these skills to solve practical problems. A.4b Justify steps used in solving equations. Use a graphing calculator to check your solutions. Objectives :. To Solve an Equation means. To isolate _______________________
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Solving Equations Using Addition and Subtraction (3.1) • A.4f Apply these skills to solve practical problems. • A.4b Justify steps used in solving equations. • Use a graphing calculator to check your solutions. Objectives:
To Solve an Equation means... • To isolate _______________________ _________________________________ • Ex: x = 5 is solved for _____. • y = 2x - 1 is solved for _____.
Addition Property of Equality For any numbers a, b, and c,____________________________ What it means: You can add any number to _______ ______of an equation and the equation will still hold true.
An easy example: We all know that 7 = 7. Does 7 + 4 = 7? _________ But 7 _______ = 7 _______. The equation is still true if we add 4 to ________ _________.
Let’s try another example! x - 6 = 10 Always check your solution!!
What if we see y + (-4) = 9? Recall that y+(-4)=9 is the same as ___________. Check your solution!
How about -16 + z = 7? Remember to always use the sign in front of the number. 16 is negative, so we need to add 16 to both sides. Check you solution!
A trick question... -n - 10 = 5 +10 +10 -n = 15 • Do we want -n? _____________________________ • If the opposite of n is positive 15, then n must be negative 15. • Solution: _____________ Check your solution!
Subtraction Property of Equality • For any numbers a, b, and c, ________________________ What it means: • You can subtract any number from ________ _______of an equation and the equation will still hold true.
3 Examples: 1) x + 3 = 17 2) 13 + y = 20 3) z - (-5) = -13
Solve x + 2 = -3To get the variable by itself, what is your first step? • Add 2 to both sides • Subtract 2 from both sides • Add 3 to both sides • Subtract 3 from both sides
Solve 8 = m - 3 • m = 5 • m = 11 • m = 24 • m = 8/3
Solve -y – (-3) = 7 • y = 10 • y = 4 • y = -10 • y = -4