1 m = 100 cm....so 2.5 m = (2.5 * 100) = 250 cm
a = 1st shelf
b = 2nd
c = 3rd
d = 4th
a + b + c + d = 250
b = 2a + 18
c = a - 12
d = a + 4
a + (2a + 18) + (a - 12) + (a + 4) = 250
5a + 10 = 250
5a = 250 - 10
5a = 240
a = 240/5
a = 48 cm <== 1st shelf
b = 2a + 18 = 2(48) + 18 = 114 cm <== 2nd shelf
c = a - 12 = 48 - 12 = 36 cm <== 3rd shelf
d = a + 4 = 48 + 4 = 52 cm <== 4th shelf
so 2nd shelf is 114 cm
Answer:
(-3, 4)
General Formulas and Concepts:
<u>Pre-Algebra</u>
Order of Operations: BPEMDAS
- Brackets
- Parenthesis
- Exponents
- Multiplication
- Division
- Addition
- Subtraction
Equality Properties
- Multiplication Property of Equality
- Division Property of Equality
- Addition Property of Equality
- Subtraction Property of Equality<u>
</u>
<u>Algebra I</u>
- Terms/Coefficients
- Coordinates (x, y)
- Solving systems of equation using substitution/elimination
Step-by-step explanation:
<u>Step 1: Define Systems</u>
3y = -5x - 3
y = -x + 1
<u>Step 2: Rewrite Systems</u>
Equation y = -x + 1
- [Multiplication Property of Equality] Multiply everything by -3: -3y = 3x - 3
<u>Step 3: Redefine Systems</u>
3y = -5x - 3
-3y = 3x - 3
<u>Step 4: Solve for </u><em><u>x</u></em>
<em>Elimination</em>
- Combine 2 equations: 0 = -2x - 6
- [Addition Property of Equality] Add 6 on both sides: 6 = -2x
- [Division Property of Equality] Divide -2 on both sides: -3 = x
<u>Step 5: Solve for </u><em><u>y</u></em>
- Define original equation: y = -x + 1
- Substitute in <em>x</em>: y = -(-3) + 1
- Simplify: y = 3 + 1
- Add: y = 4
