Solve using elimination. 3x + 9y = –15 –5x − 9y = –5

Mathematics

1 answer:

morpeh [17]2 years ago

3 0

Answer:

(x, y) = (10, -5)

Step-by-step explanation:

3x + 9y = -15 (eq 1)

-5x - 9y = -5 (eq 2)

add equation 1 and 2

3x + 9y -5x -9y = -15 - 5

-2x = -20

x = 10

put value of x in equation 1

3(10) + 9y =-15

30 + 9y = -15

9y = -45

y = -5

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Evaluate y = 2x + 1 when x = 1

Solnce55 [7]

Answer:

y = 3

General Formulas and Concepts:

Pre-Algebra

Order of Operations: BPEMDAS

Brackets
Parenthesis
Exponents
Multiplication
Division
Addition
Subtraction

Left to Right

Step-by-step explanation:

Step 1: Define

y = 2x + 1

x = 1

Step 2: Evaluate

Substitute in x: y = 2(1) + 1
Multiply: y = 2 + 1
Add: y = 3

5 0

2 years ago

(5x^3-8x^2+9x+12)/(x-3) please answer with sentences on how to do it step by step. thanks!

Anastaziya [24]

Answer:

$5x^2+7x+30+\frac{102}{x-3}$

Step-by-step explanation:

$\mathrm{Divide\:the\:leading\:coefficients\:of\:the\:numerator\:}5x^3-8x^2+9x+12\\\mathrm{and\:the\:divisor\:}x-3\mathrm{\::\:}\frac{5x^3}{x}=5x^2\\\mathrm{Quotient}=5x^2\\\mathrm{Multiply\:}x-3\mathrm{\:by\:}5x^2:\:5x^3-15x^2\\\mathrm{Subtract\:}5x^3-15x^2\mathrm{\:from\:}5x^3-8x^2+9x+12\mathrm{\:to\:get\:new\:remainder}\\\mathrm{Remainder}=7x^2+9x+12\\\mathrm{Therefore}\\=5x^2+\frac{7x^2+9x+12}{x-3}$

$\mathrm{Divide\:the\:leading\:coefficients\:of\:the\:numerator\:}7x^2+9x+12\\\mathrm{and\:the\:divisor\:}x-3\mathrm{\::\:}\frac{7x^2}{x}=7x\\\mathrm{Quotient}=7x\\\mathrm{Multiply\:}x-3\mathrm{\:by\:}7x:\:7x^2-21x\\\mathrm{Subtract\:}7x^2-21x\mathrm{\:from\:}7x^2+9x+12\mathrm{\:to\:get\:new\:remainder}\\\mathrm{Remainder}=30x+12\\\mathrm{Therefore}\\=5x^2+7x+\frac{30x+12}{x-3}\\$

$\mathrm{Divide\:the\:leading\:coefficients\:of\:the\:numerator\:}30x+12\\\mathrm{and\:the\:divisor\:}x-3\mathrm{\::\:}\frac{30x}{x}=30\\\mathrm{Quotient}=30\\\mathrm{Multiply\:}x-3\mathrm{\:by\:}30:\:30x-90\\\mathrm{Subtract\:}30x-90\mathrm{\:from\:}30x+12\mathrm{\:to\:get\:new\:remainder}\\\mathrm{Remainder}=102\\\mathrm{Therefore}\\=5x^2+7x+30+\frac{102}{x-3}$