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What are the x-intercepts of the graph pf the function below?
y=x^2+3x=28

2 Answers

5 votes
To solve this, you need to subtract 28 from both sides, then solve.

y=x^2+3x-28

The x-intercepts are (-7,0) and (4,0)
User Fxdxpz
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1 vote

Answer: The required x-intercepts are (4, 0) and (-7, 0).

Step-by-step explanation: We are given to find the x-intercepts for the parabola defined by the following equation :


y=x^2+3x-28~~~~~~~~~~~~~~~~~~~~~~~~~(i)

We know that

the x-intercepts of a function are the points where the y co-ordinate is zero.

So, from equation (i), we have


y=0\\\\\Rightarrow x^2+3x-28=0\\\\\Rightarrow x^2+7x-4x-28=0\\\\\Rightarrow x(x+7)-4(x+5)=0\\\\\Rightarrow (x-4)(x+7)=0\\\\\Rightarrow x-4=0,~~~x+7=0\\\\\Rightarrow x=4,~-7.

Therefore, the x-intercepts of the given function are (4, 0) and (-7, 0).

User Andrew Hubbs
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6.2k points