Q. Let m=2x+3.Which equation is equivalent to (2x+3)2−14x−21=−6 in terms of m ?Choose 1 answer:(A) m2−7m+6=0(B) m2+7m+6=0(C) m2+7m−15=0(D) m2−7m−15=0
Given substitution equation: We are given the substitution m=2x+3. We need to find an equivalent equation for the expression (2x+3)2−14x−21=−6 in terms of m.
Expand and simplify expression: First, let's expand the expression (2x+3)2−14x−21 and simplify it.(2x+3)2−14x−21=(2x+3)⋅(2x+3)−14x−21=4x2+6x+6x+9−14x−21=4x2+12x−14x+9−21=4x2−2x−12
Equation simplification: Now, we equate the simplified expression to −6, as given in the original equation.4x2−2x−12=−6
Isolate terms and replace: To find the equivalent equation in terms of m, we need to isolate the terms with x and replace them with m. Let's add 6 to both sides of the equation to simplify it further.4x2−2x−12+6=−6+64x2−2x−6=0
Substitute x in terms of m: Now, we can substitute m for 2x+3 in the equation.Since m=2x+3, we can solve for x in terms of m:2x=m−3x=2m−3
Simplify equation with substitution: We substitute x in the equation 4x2−2x−6=0 with the expression we found in terms of m.4(2m−3)2−2(2m−3)−6=0
Combine like terms: Now, we simplify the equation by squaring the term and multiplying through by 4.4×(4m2−6m+9)−(2m−6)−6=0(m2−6m+9)−(2m−6)−6=0
Combine like terms: Now, we simplify the equation by squaring the term and multiplying through by 4.4×(4m2−6m+9)−(2m−6)−6=0(m2−6m+9)−(2m−6)−6=0We continue to simplify the equation by combining like terms.m2−6m+9−2m+6−6=0m2−8m+9=0
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