A two digit number has a tens digit and a ones digit.
Let's say x = tens digit and y = ones digit
"The sum of the digits is 5"
x + y = 5
The next phrase is "the number multiplied by 3 is 42" but we need to represent the number using the digits. So they need to be multiplied first by their place value and added together. [Example: 34 = 3(10) + 4(1)]
The number is: 10x + y
3(10x + y) = 42
The system of equations: (two equations for two unknowns)
x + y = 5
30x + 3y = 42
Then you can use substitution or elimination to combine and solve.
I'll use elimination, multiply the entire top equation by -3 and add the equations together. y will cancel out
-3x - 3y = -15
30x + 3y = 42
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27x + 0 = 27
x = 1
then plug x = 1 into either equation to find y
1 + y = 5
y = 4
remember the x and y represent digits so the number xy is 14
To do these, start by looking at the "b" value -6.
divide it by 2
-6/2 = -3
now square this number
(-3)^2 = 9
this is what you need for the "c" value
there is only a 5 for the c value so add 4 to both sides of the equation. ( +4 = +4)
y +4 = x^2 -6x +5 +4
y +4 = x^2 -6x +9
y +4 = (x -3)^2
y = (x -3)^2 - 4
vertex ( 3, -4) upwards facing like a bowl, because the "a" value is positive. So the vertex is the minimum, lowest point on the graph.
2x - 3y = 7 can be rewritten as y = 2/3x - 7/3, therefore, the equation that is a linear equation is: C. 2x - 3y = 7.
<h3>What is a Linear Equation?</h3>
A linear equation is expressed in the slope-intercept form as y = mx + b.
2x - 3y = 7, rewritten in slope-intercept form would be:
-3y = -2x + 7
y = -2x/-3 + 7/-3
y = 2/3x - 7/3
m = 2/3 and b = -7/3
Therefore, the equation that is a linear equation is: C. 2x - 3y = 7.
Learn more about linear equation on:
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Answer:
1. 144 2.16 3. 1 4. 1.69
Step-by-step explanation:
