Q. Let p=x2−7. Which equation is equivalent to (x2−7)2−4x2+28=5 in terms of p? Choose 1 answer: (A) p2−4p+23=0(B) p2+4p−5=0(C) p2−4p−5=0(D) p2+4p+23=0
Substitute p into equation: Given p=x2−7, we need to express the equation (x2−7)2−4x2+28=5 in terms of p.
Express −4x2 in terms of p: First, let's substitute p into the equation where we see x2−7. This gives us p2−4x2+28=5.
Distribute −4 across terms: Now, we need to express −4x2 in terms of p. Since p=x2−7, we can rewrite x2 as p+7. Therefore, −4x2 becomes −4(p+7).
Simplify the equation: Substitute −4(p+7) into the equation in place of −4x2. This gives us p2−4(p+7)+28=5.
Subtract 5 from both sides: Now, let's distribute the −4 across the terms inside the parentheses: p2−4p−28+28=5.
Express equation in standard form: The −28 and +28 cancel each other out, simplifying the equation to p2−4p=5.
Express equation in standard form: The −28 and +28 cancel each other out, simplifying the equation to p2−4p=5.To get the equation in standard form, we subtract 5 from both sides, resulting in p2−4p−5=0.
Express equation in standard form: The −28 and +28 cancel each other out, simplifying the equation to p2−4p=5.To get the equation in standard form, we subtract 5 from both sides, resulting in p2−4p−5=0.We have now expressed the original equation in terms of p, and the equivalent equation is p2−4p−5=0, which corresponds to option (C).
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